Perfect Digestion

A hay-based diet that is grain and soy-free ensures a healthy digestive system. This is because rabbits, guinea pigs, and chinchillas are dependent on the good bacteria that live in their digestive tract. These bacteria ferment and break down the undigested fiber contained in the food the bunny eats. They actually live in a “chamber” near the end of the digestive tract called the caecum (see picture below). This means that they are able to digest and extract nutrients out of their food before the bacteria have a chance to ferment (digest) it. Consequently rabbits, guinea pigs, and chinchillas are very sensitive to foods they cannot digest because they cause problems with fermentation in the caecum (starch and other items).

Large Intestine:
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This is where water is re-absorbed prior to expelling little poops.
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This is where most of the magic happens… Normally undigested hay that is rich in cellulose provides food for healthy bacteria that slowly break it down and produce energy, vitamins, and other nutrients for the rabbit, guinea pig, or chinchilla.

However this special symbiotic arrangement can spell trouble for if it eats too much grain or soy. These items are like candy for bad bacteria and can quickly change the pH and other conditions in the caecum leading to digestive upset, bloat, and possibly even diarrhea.

more info ∇

This is the end of the small intestine where most of the nutrients should have already been absorbed. After passing through this part the micro-villi of the intestinal wall separates particles according to their size.

Large particles (or long-stem fiber that is greater than 1.7mm in size for rabbits – primarily comes from lignified or woody stems that resist being broken down during chewing) are directed to the large intestine while the small particles (smaller than 1.5mm for rabbits) are directed into the caecum and fuel bacterial fermentation.

Small Intestine:
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All of the nutrients that have been released through digestive processes that occur in the stomach and in the small intestine are absorbed as they pass through here. The small intestine is a long and narrow tube that is small in diameter to aid in the absorption of nutrients.

However starch (from grain sources like wheat middlings and grain by-products) are not fully broken down and therefore cannot be absorbed.

At the end of the small intestine (the ileum) all food particles that have not already been absorbed are sorted according to size. Large particles (this is where the term “long-stem fiber” comes from) are directed to the large intestine while small particles are directed into the caecum to be fermented (digested by bacteria).

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The stomach is not the location where digestive problems actually occur. In rabbits, guinea pigs, and chinchillas the majority of the problems occur in the caecum.

HEALTHY FERMENTATION: The special arrangement of the digestive system means that only indigestible material (mostly fiber) provides the foundation for the slow growth of healthy bacteria. This process has the potential to provide additional nutrients such as B-vitamins, essential amino-acids (high quality protein) and volatile fatty-acids (a natural source of energy).

STARCH AND SOY CAUSE PROBLEMS: Take note that rabbits, guinea pigs, and chinchillas don’t digest starch (from grain and grain by-products) or soy very well.

Too Many Fresh Greens and Veggies can Cause Problems

Rabbits, guinea pigs, and chinchillas also cannot directly digest even the soft simple fibers like pectin or hemicellulose found in vegetables, leafy greens, and fresh grass. Too much of any of these things will lead to the rapid growth of bad bacteria and lead to bloat, mushy poops, uneaten caecotrophs or other digestive problems. It is ok to feed greens as long as they are eating enough hay which provides bulk to slow down bacterial fermentation. For this reason, when feeding greens, it is best to spread it out and feed small amounts throughout the day rather than one big salad.

Better Urine

Low Calcium Diet?

Bladder sludge and stones are a common problem for rabbits, guinea pigs, and chinchillas. Many mistakenly feel they are due to the naturally high calcium content of their diet and this has led to a ‘push’ for low calcium diets and a fear of not feeding foods containing oxalate (like spinach). However, the unspoken danger of a low calcium diet is the loss of bone mineralization (metabolic bone disease leading to dental disease), something veterinarians are beginning to look into.

Calcium is not the Problem

Research has suggested that even extra high dietary calcium levels (as high as 2.3%) do not appear problematic for rabbits, guinea pigs, and chinchillas as long as you don’t add vitamin D3 (Clauss et. al. 2012). A PhD nutritionist at the 2014 HRS EDUCATORS CONFERENCE presented research that clearly showed that there is no correlation between urine sludge or stones and a high dietary or blood serum calcium level (research was performed more than 10 years earlier).

Feeding greens to increase water consumption?

Dietary Oxalate isn’t the Problem

Oxalate binds to calcium and causes it to precipitate. Dietary oxalate actually binds to calcium in the digestive tract and therefore prevents its absorption. The calcium (and oxalate) is then eliminated in the little poops. Consequently dietary oxalate is not likely to be absorbed and therefore cannot cause calcium precipitation in the urinary tract.

Oxalates actually form in the body as an abnormal by-product of metabolism. Scientists are discovering that increased levels of oxalate may be due to a deficiency in vitamin B6. Although it is impossible to totally prevent the formation of oxalate in the body a balanced diet does minimize it. Oxalate that is formed and not metabolized ends up in the urinary tract and precipitates calcium and forms sludge and stones. The body has a natural defense against this. It produces a protein that binds to oxalate so that it doesn’t float around free and end up binding to calcium. This way oxalate can be safely disposed of in the urine. Remember, a healthy diet containing a balance of the essential amino acids is necessary to optimize the formation of this and other needed proteins/enzymes.

What Causes Stones/Sludge?

A well documented culprit of urinary sludge/stones is bacterial infection. Infection of the urinary tract causes an unnaturally high pH that promotes struvite crystal (kidney/bladder stone) formation even in pets whose diets are low in calcium. This increase in pH is caused by the bacterial deamination of urea.

Calcium Carbonate Sludge

Bicarbonate that is excreted into the urine is the problem. Bicarbonate chelates (binds) with calcium and precipitates it into stones/sludge (calcium carbonate is actually about 60% carbonate by weight). A high urine pH increases the amount of calcium-carbonate. This is the most common cause for sludge and stones commonly found in the urine of rabbits, guinea pigs, and chinchillas. A lower urine pH titrates or dissolves bicarbonate into CO2 and water thereby removing the bicarbonate and freeing the calcium to be dissolved into solution… it magically disappears!

Works Cited

Nouaille, L., Lebas, F., Mercier, P. (1994). Calcification de l’aorte : une lesion relativement frequente. Cuniculture, 21 (120), 274-276.

Bindels R. J., Hartog A., Abrahamse S. L., Van Os C. H. 1994. Effects of pH on apical calcium entry and active calcium transport in rabbit cortical collecting system. American Journal of Physiology 266: F620-F627

Clauss M., Burger B., Liesegang A., Del Chicca F., Kaufmann-Bart M., Riond B., Hassig M., and Hatt J.-M. 2012. Influence of diet on calcium metabolism, tissue calcification and urinary sludge in rabbits (Oryctolagus cuniculus). Journal of Animal Physiology and Animal Nutrition 96:798–807

Kamphues J., Carstensen D., Schroeder D., 1986 Effects of increasing calcium and vitamin D supply on calcium metabolism of rabbits. J Anim Physiol Anim Nutr 56:191–208.

More Energy

A balanced diet fortified with trace elements and B-vitamins supports healthy energy levels. Optimizing nutrition can change a sluggish rabbit into a binkying’ bunny. The same goes for guinea pigs and chinchillas!

Probiotic Support

A high fiber diet (of the right types and sizes) supports healthy digestive patterns and energy levels. It does this by supporting good bacterial fermentation patterns in the caecum which constantly replenish the blood stream with new B-vitamins and energy sustaining volatile fatty acids.


Soy protein or starch from grains or middlings and grain-by-products can promote the growth of bad bacteria that can cause bloat or other digestive problems leaving rabbits, guinea pigs, and chinchillas in a lethargic and potentially fatal condition. For this reason it is important for them to consume a hay-based diet rather than one containing too much grain or soy.

Omega 3’s and 6’s

Getting the right types of fat in the diet is a critical part of a properly balanced diet. Adding flax seed (a great source of omega 3’s) and other non-gmo healthy oil seeds to the diet greatly improves the quality of the fur coat which is an outer reflection of the internal health.

When adding healthy oils to the diet it is best to use whole natural oil seeds (ground fresh) that are rich in natural vitamin E because the ratio of fat to vitamin E in the diet needs to be balanced. Rendered animal fats or refined soy or vegetable oil are devoid of natural vitamin E and should be avoided.

Less Odor

A balanced diet means less protein waste and litter box smell. What causes protein waste? How much protein do rabbits, guinea pigs, and chinchillas need to stay healthy? How much is too much?

These are simple questions with complex answers… because it ‘depends’ upon many factors. However it is VERY EASY to tell if the protein in the food you are feeding is getting wasted. This is because wasted protein will cause your pet’s litter box (urine) to stink (ammonia)… and the smell gets worse as more protein is wasted.

Balanced Diet

The Importance of Balanced Dietary Protein

Did you know that a rabbit, guinea pig, or chinchilla can be DEFICIENT in meeting its dietary needs for protein AND simultaneously be wasting protein? Let me explain.

Dietary protein is broken down into individual amino acids. In our example they are colored beads.

Our pets then string these amino acids together in unique combinations (like beads on a string) to build new proteins found in places such as the immune system, fur, muscles, and organs. There are literally many 10,000’s of unique proteins. A lack of protein compromises health!

Each color represents an individual type of amino acid. There are 20 different amino acids to choose from. 12 of them can be interchanged or converted from one ‘color’ into another. However the other 8 are labeled as ‘essential’ because they cannot be converted and have to be obtained in the diet. If you run out of a particular color then you’ll have to eat more food to supply an additional “pile of beads” and look for the color you need OR skip making the needed protein and compromise the health of your pet. In either case, what do you do with the rest of the beads you don’t use? Unused protein has to be processed and eliminated. Normally this produces urea excreted in urine but excessive levels of wasted protein or other dietary imbalances triggers renal ammoniagenesis leading to excess litterbox odor and urinary sludge.


The smell of ammonia comes from wasted protein. It is impossible for the waste of living things to be “ammonia free.” However excessive ammonia is an obvious sign that protein in the food is not getting used EVEN IF IT IS GETTING DIGESTED AND ABSORBED! In fact the liver and kidneys have to work hard to rid the body of unused protein which comes out in the urine and is released in the litterbox into the ammonia that you smell.

Maintaining a Healthy Weight with Balanced Protein

If your pet is deficient in a single amino acid while making a protein (missing a few colored beads) then they will go without the needed protein/enzyme (like a mechanic without the right tools) and their health will be compromised.

To some extent pets can compensate simply by eating more food to obtain more amino acids but this leads to two problems. First, they will have to dispose of all the unused protein which stresses the liver and kidneys. Second, eating too many calories will cause them to gain unhealthy weight.

True Ileal Digestibility

Balancing the “amino acid profile” should be according to the digestibility or bio-availability for each individual essential amino acid. Sherwood Pet Health’s premium food is balanced according to the “true ileal digestibility” (the best way) of all the 11 essential amino acids (and it also includes chelated selenium for those of you who know about selenocysteine, the 21st proteogenic amino acid used in the all important anti-oxidant thioredoxin reductase enzyme).


Sherwood Forest rabbit food is SOY-FREE! Soy contains higher levels of “trypsin inhibitors” that inactivate protein digestive enzymes. This reduces the digestibility of the protein so it is not fully absorbed before it gets to the caecum. Remember this promotes the growth of bad bacteria in the caecum. Their growth produces ammonia as a by-product which changes the pH and leads to digestive troubles.

Soy is also not a natural food for rabbits, guinea pigs, and chinchillas and so they are not adapted to the protein in it. As a consequence the amino acids are out of balance causing increased protein waste and higher risk for urinary sludge.

Healthy Weight

Sherwood formulas will help your rabbit, guinea pig, or chinchilla burn excess body fat and gain healthy weight. This is accomplished because Sherwood foods provide optimized nutrition and are low in total calories and simple carbohydrates.

Optimized Nutrition

Nutrition has many layers that, when properly balanced, work together for optimal health. We at Sherwood Forest clearly understand that proper nutrition is the basis for healthier and hoppier pets. This is why our formulas are built on a foundation of whole natural ingredients that are scientifically balanced with all the trace elements and micronutrients needed to promote optimal health.

Calories? How many and what kind…

Our pets regulate the amount of food they eat based upon the energy and protein concentration of the diet. This means that they tend to eat less food that is calorie dense and, conversely, they tend to eat more food if it is low in calories and protein. However, this has NOTHING TO DO WITH WHETHER OR NOT YOUR RABBIT, GUINEA PIG, OR CHINCHILLA GETS FAT!!!

The “Fat” culprit

The main contributing factor that causes your pet to store excess body fat is the balance of other nutrients available in the food. This is because any single dietary nutrient that is ‘deficient’ effectively causes all other nutrients to be in ‘excess,’ especially calories! Calories in ‘excess’ are stored as fat. Essentially an unbalanced diet causes them to gain unhealthy weight.

Say NO to CARB’s!

Did you know that ALL other brands contain significant amounts of grain and grain-by-products? A diet too high in carbohydrates will store the excess energy as body fat. Furthermore a balanced diet with a healthy protein to energy ratio helps keep rabbits, guinea pigs, and chinchillas at an ideal body weight by promoting the burning of excess body fat and preventing additional fat storage.

Results you can see

As a result you will see your pet gain improved muscle tone and overall health as well as lose excess body fat. If you read through the reviews you’ll find many stories of both older and younger rabbits, guinea pigs, and chinchillas that have benefited in these specific ways since they switched to Sherwood.

Easy Transition

Switching to Sherwood’s hay-based formula is easier on your pet. The reason why it is popular to slowly switch the diet of a rabbit, guinea pig, or chinchilla over a period of days to weeks is to prevent the rapid growth of bad bacteria as they adjust to a new diet. This is most likely to occur when the switch is introducing more carbohydrates (or a different source) and/or soy into the diet.

Switching from a grain/soy-based diet to a hay-based diet is a lot easier on your pet. In fact most rabbits, guinea pigs, and chinchillas can make the switch in a single day although some resist switching to this healthier diet. For this reason it is best to mix the new food with the old food for a while. However, don’t be surprised if your pet picks out and only eats the new fresher Sherwood Food!


rabbits, guinea pigs, and chinchillas are a special kind of herbivore sometimes referred to as a ‘FIBERvore’. This is because their primary diet is tough fibrous plant material. In the wild it is a mixture of grasses (like timothy or orchard hay) and legumes (like clover or alfalfa). It is important to note that these plants are actually composed of a number of different types of fiber that, for the purposes of nutrition, can be classified into two generalized groups. For this reason a food label that reports a guaranteed minimum/maximum amount of fiber does not provide enough detail.


Click the picture and take a close look at the different particle sizes that are important for proper digestion.

There are some visual cues that can help you in deciding if the food contains enough of the right types (AND SIZES) of fiber. Look at the picture of pellets. The particles in the pellets should be of various sizes (read the next paragraph) instead of uniformly ground into small particles.

Long Stem Hay provides the indigestible fiber rabbits, guinea pigs, and chinchillas need to keep their digestive tract active and healthy. The actual length of what is considered long-stem fiber will probably surprise you.

Long stem fiber is actually every particle in the digestive tract that is longer than 1.7 mm (for rabbits or smaller for guinea pigs, and chinchillas). That is only 7/100th of an inch! However, this is very long for the intestinal villi near the end of the small intestine where food particles are sorted according to size.

Most particles that are 1.7mm or longer get transported to the large intestine where water is reabsorbed before they are expelled. Particles smaller than 1.5 mm (for rabbits) are shuttled into the caecum where they are fermented (eaten by bacteria). This process produces energy for (volatile fatty acids) as well as many B-vitamins (needed to use the energy) and other nutrients.


rabbits, guinea pigs, and chinchillas need to regularly eat and drink to help support the growth of healthy bacteria. ALWAYS PROVIDE THEM WITH HEALTHY FOOD AND CLEAN WATER. If anything disrupts this fermentative process then the production of B-vitamins and fatty acids will stop and your pet will loose its energy levels and its appetite. If this goes on for too long then they could die.


There are many foods people commonly give to rabbits, guinea pigs, and chinchillas that can also trigger bad fermentative patterns that lead to the same problems. This includes anything that is high in sugar or starch as well as many veggies that are rich in soft fibers like pectin or hemicellulose. These foods have to be limited in the diet. Signs that they have eaten too much of these foods include mushy poops, bloating, uneaten caecotrophs and, in extreme situations, even G.I. stasis or diarrhea. Click here for more detailed information with pictures.

Say NO to Soy!

There are many reasons why we don’t use soy in anything we do. Here are a few reasons. First soy contains high levels of a anti-nutritional factor called phytate (phytic acid). Phytate binds to minerals so that your pet cannot absorb them and this can lead to many, many problems including stunted growth and poor health.

Why do other brands use soy? It is used as the primary source of protein but ironically it contains trypsin inhibitors preventing your pet from properly digesting it leading to caecal fermentation problems.

Soy contains significant levels of phytoestrogens that are potent antithyroid agents. Chronic doses can lead to thyroid problems including hypothyrodism, cancer, and autoimmune thyroid disease. Signs that these things are occurring include low energy levels, weight gain, and problems with metabolism.

There are many other dangers of using soy that are not listed here. However did you know that it is a major contributor to the smell in the litter box?

Softer Fur

Beautiful fur is a reflection of inner health. Although true health is more than fur deep you’ll see a big difference in the quality of your pets fur within a few weeks of switching to Sherwood. Even during molting season you’ll notice that the fur will grow back more quickly and healthier. This is true even for angora or long-haired breeds.

My bunnies LOVE it – and i do too!

Posted by Bees On Earth

We’ve been buying Sherwood Forest Natural rabbit food for 3 years now. Not only do Chocolate, Treble and Moo Cow all love the pellets, no other food provides them the sheen and shine and quality of their fur.

His fur has improved, his energy is amazing!
Posted by Jamie

Though I was fairly happy with Oxbow and even sometimes Ecotrition organics for my rabbit along with the best hay money could buy I researched some and found out about you and your amazing food. A few weeks ago I purchased a bag for my rabbit.

Softest fur ever!
Posted by Lisa N.

Love the food; the bunnies love it too. It's good knowing how fresh it is.

The best!
Posted by Brenda Mealey

Sherwood Forest is the best rabbit food there is! All six of my bunnies love it. Their fur looks so much better and they are all healthier. My vet also thinks it is the best!

A Hoppier bunny indeed!
Posted by Unknown

My bunny was having terrible troubles with fecal. That's all gone now ! He's noticeably happier with lots of spunk and dance! His fur is growing like crazy and his coat is nice and soft. And he loves his food! His appetite has tripled too!!! Enjoys being hand fed as well !

Silkier fur
Posted by Unknown

>I ordered this food for my rabbit Scout and my MIL's rabbit Andy. Andy's fur was thin and wire like. It is amazing, but after 2 weeks on this food, he has soft, shinier and thicker fur. Scout's fur is even softer than it was. They love this food and we love what it is doing for their coats.

Luxurious rabbit!
Posted by Unknown

>My bun is three years old; I just switched him to SF in December after a friend told me about it. Nein loves the new food and is doing very well health wise. When I had him in the vet's office two weeks ago the vet commented while petting him, "This rabbit's fur is so luxurious!" – I highly recommend Sherwood Forest.

Bunnies go crazy for this stuff!
Posted by Ashley

The first time I got my free box my buns were hopping with joy! Their fur looks excellent and my big girl is looking slimmer each day. If it makes them happy, it make me happy. (:

I only do what the little voices tell me to do
Posted by Amy G

And the little voices of Chocolate, Treble and Moo Cow insist upon Sherwood Forest Natural Rabbit Food! My angoras' fur GLEAMS with vibrant health. Every once in a while I forget to re-order on time and we run out before our next shipment can travel across the country. Then my bunnies have to make do with feed store pellets. The change in their fur and energy level is immediate. The bunnies have spoken!

Best food!
Posted by Heather

I have 3 rabbits. I've had 5 in my entire life. So I've tried a lot of food. My rabbits love this food! It's the food they've enjoyed the most. Plus the ingredients don't make me scared regarding extra sugars, wheat, and other ingredients that are not healthy for them. They seem full of energy and have shiny fur. I also feel confident they are getting enough hay in their diet, as these pellets have hay.

His fur has improved, his energy is amazing!
Posted by Jamie

Though I was fairly happy with Oxbow and even sometimes Ecotrition organics for my rabbit along with the best hay money could buy I researched some and found out about you and your amazing food. A few weeks ago I purchased a bag for my rabbit.

Rex is fairly picky but he is now running across the 12×10 room to eat some of your delicious and nutritious product. His fur has improved, his energy is amazing, he is doing so well on your food,,,and its beautiful to see.

Thank you very much David!!

I wouldn't give them anything else
Posted by Alexis Y.

My 3 Holland Lop bunnies were having trouble staying at the correct weight. Then I saw Sherwood Forest online, and I figured I would try it out. When I first opened the bag I noticed that it smells much fresher then the other pellets, and the color looked much better too. My rabbits gobbled it down as soon as I gave to them. Since then they have not had any more weight problems, and their fur looks fantastic! I have been feeding it to them for almost a year now, and I wouldn't give them anything else. The only reason it is 4 stars is because of the price. The good news is that if you buy in bulk, it is a little more affordable.

Fresh awesome food
Posted by Nola and Rupert

If my bunnies can talk, they probably will be saying this, "We love Sherwood pellets. We would try to act cute by begging for more and our owner would never resist us. Thanks Sherwood for making our tummy healthy and fur shiny and beautiful. That makes us bink and show funny tricks to make our owner happy. Now, everyone is happy."

Probably not like that but I assume it's close enough. Thanks Sherwood for such great product

My rabbit likes it better than Oxbow
Posted by Unknown

My Flemish Giant is 3 years old and is a house rabbit. She's been healthy all these years but suddenly developed soft poo that would stick to her behind. I researched and discovered the pellets and hay I had been giving her all her life could be the cause. I bought her the Oxbow brand food and Oxbow brand hay. Very expensive. In trying to find a site where I could buy it cheaper I found this site. I got the free sample to check it out. I mixed the Oxbow with this food and my rabbit picked through it. I wasn't sure which brand she really wanted so I put two bowls in her cage. One with Oxbow and one with Sherwood. She ate the Sherwood and didn't touch the Oxbow. I'm happy to say she is back to being healthy and happy and no more messy backside. Her fur is soft and shiny. I wish I had known about this food 3 years ago when I got her. These are the only pellets I will buy her from now on.

Rex is fairly picky but he is now running across the 12×10 room to eat some of your delicious and nutritious product. His fur has improved, his energy is amazing, he is doing so well on your food,,,and its beautiful to see.

Thank you very much David!!

Excellent Teeth

PDF Pamphlet on Dental Health – more details

Proper dietary mineral balance plays a key and yet often overlooked role supporting proper teeth alignment and wear in small herbivores like rabbits.

Two Hypotheses and Recent Research

Small herbivore dental health isn’t fully understood. Currently there are two prevailing hypotheses that may explain the current prevalence of dental disease among the pet population. These are:

Hypothesis 1. Rabbits, guinea pigs, and chinchillas chew whole loose hay (which is more abrasive) differently than they chew pellets. The belief is that to prevent dental disease they must eat a diet composed primarily of loose hay.

Hypothesis 2. Metabolic bone disease (unbalanced dietary levels of calcium and phosphorous) is the root cause of dental disease that leads to malocclusion and improper tooth wear (tooth spurs on cheek teeth).

The first hypothesis is based upon the belief that the teeth of rabbits, guinea pigs, and chinchillas constantly grow so that they must eat a diet that is course enough to properly wear them down or they will overgrow. It is also believed that they chew hay differently than pellets. Specifically it is believed that they chomp up and down on pellets rather than using their normal figure 8 side-to-side chewing pattern. If this is the case then it would explain the improper tooth wear seen that leads to dental disease.

The second hypothesis is based upon the observation that rabbits, guinea pigs, and chinchillas with dental disease commonly have metabolic bone disease that weakens the bone supporting the orientation of the teeth. As a result the normal pressure of chewing causes the teeth to become crooked not allowing them to properly wear.

Testing the Hypotheses

To test the first hypotheses Müller et. al. studied the rates of tooth growth and tooth wear in rabbits fed exclusively on either whole timothy grass hay, or one of four complete pelleted diets (isocaloric and isonitrogenic) based either on alfalfa, timothy grass, timothy grass with rice hulls (more abrasive than timothy grass), or timothy grass with rice hulls and sand (2014).

The results: Müller et. al. clearly documented that the rate of tooth growth varies according to the rate of tooth wear (i.e. higher rates of tooth wear subsequently increases the rate of tooth growth). They also found that the rate of cheek tooth wear varies in a gradient depending upon the position of the tooth in the cheek tooth row (distal teeth are worn faster than proximal because they have more contact with food). Interestingly all diets had similar wear patterns with no signs that would indicate the development of dental disease except the diet containing sand which showed dental abnormalities because of excessive wear. They also found that the “chewing action of cheek teeth is more independent of whether the diet is offered whole or pelleted.” As a result they concluded that the previous belief that rabbits spend more time chewing pellets vertically (chomping pellets believed to be the cause of tooth spurs on cheek teeth because of improper wear) instead of the horizontal ‘figure 8’ type motion used to chew hay was INCORRECT. Instead their research identified that rabbits actually chew hay and pellets the same way with their cheek teeth and that the wear patterns were not different.

In their own words: “Based on these findings, it is our opinion that diet alone may be less likely to cause dental problems in pet rabbits, due to flexible growth that reacts to wear. Other causes such as mineral imbalances or genetics should be considered when diagnosing dental disease, and a minerally balanced diet and breeding hygiene (not allowing affected animals to reproduce) may be the most promising prophylactic approaches.” This means that they concluded that hypothesis 2 is more likely the cause of dental disease.

Another Study With Seemingly Conflicting Results

In contrast another report published less than a year later by Meredith et. al. concluded that a low intake of forage was primarily responsible for dental disease and that metabolic bone disease was not implicated in the development of dental disease (2015). They compared feeding rabbits a grass hay only diet, an extruded diet with hay, a grain-based muesli mixed diet with hay, and a muesli mixed diet only (without hay).

They found very similar results clearly showing that tooth growth rate correlated strongly with tooth wear rate and that the effect on each tooth was independent. However they found that the muesli diet (with or without hay) lead to dental abnormalities and tooth spurs. Their conclusion was that the museli diet did not wear the tooth surface properly and that abnormal tooth wear was implicated in the development of dental disease and not metabolic bone disease. To prove their point they calculated the effect that selective feeding of the muesli diet had on the balance and the percentage of dietary calcium and phosphorous.

However… results actually point towards Metabolic Bone Disease

However, their study actually supports the likelihood that metabolic bone disease was responsible for the observed dental disease. This is because the authors conclusion was not based upon measuring the actual calcium consumed and absorbed. If the authors had quantified the amount of food/hay consumed then a simple estimate of actual bioavailable calcium consumed would likely identify that the rabbits were indeed deficient in calcium and that the cause of the dental abnormalities are due to metabolic bone disease.

For example, the diets they fed claimed to provide a total calcium of no more than 0.6%. This is borderline deficient in calcium for optimal bone mineralization. Optimal bone mineralization requires diets at least as high as 1.0% (Noris et. al. 2001) and the aveloar bone (teeth sockets) is the most prone to being affected by a low-calcium diet. Furthermore the authors did not verify the claim by measuring the actual calcium content of the diets they fed. Neither did they consider the effect of the bioavailablility of the calcium (some of the dietary calcium is expected to be bound to plant material or the added dietary phosphorous which was high relative to the calcium in the diet). Also, diets based on grain and soy may lead to increased protein waste. For these reasons it is highly likely that the rabbits were deficient in calcium and were suffering from metabolic bone disease. Sadly the authors missed obtaining these important pieces of information that would have changed their conclusions.

More about Metabolic Bone Disease

Metabolic bone disease first affects the alveolar bone (teeth sockets) because it is actively growing tissue. If it is not optimally mineralized, then the pressure of chewing becomes increasingly likely to cause the teeth to shift within the alveolar bone. Once the teeth become slightly malloccluded then improper wear can occur. In fact it will accentuate and perpetuate the shifting of the teeth and the development of dental disease. Dental disease is well known to be associated with the curvature of the cheek teeth. Curved cheek teeth (malocclusion) are not worn properly because they do not come in proper contact with other teeth (dental attrition) and are not directly involved in chewing food (dental abrasion) and as a result are not worn properly. This is likely due to metabolic bone disease which provides a mechanism for curvature of the teeth rather than improper wear which occurs only after teeth are crooked.

Results of Current Research Supporting Hypothesis 2

Research directly testing the role of proper mineral balance in the development of dental disease has yet to be done. However, many publications in primary literature already provide strong supporting evidence for the hypothesis. These include (but are not limited to) the fact that:

1. tooth wear rate directly influences tooth growth rate

2. Rabbits, guinea pigs, and chinchillas chew hay and pellets the same resulting in proper wear patterns

3. teeth do not develop signs of dental disease until after they have become maloccluded. Malocclusion is likely because of the softening of the alveolar bone tissue (teeth sockets) due to metabolic bone disease (primarily caused by low calcium diets).

Research by a Rabbit Veterinarian

DVM Frances Margaret Harcourt-Brown, a recognized specialist in rabbit medicine and surgery in the UK, performed a detailed radiological and morphological study of 172 prepared skulls and 315 skull radiographs of pet rabbits with the collection of rabbit skulls from the Natural History Museum in London. She also examined the skulls and radiographs, gender and breed details of 1254 pet rabbits presented for veterinary care, 465 of which required dental treatment. She clearly documented that the loss of alveolar bone preceded changes in shape or structure of the crowns and root elongation in pet rabbits. Despite the wide variation in breeds analyzed (and therefore differences in skull shapes and sizes) she found no statistically significant correlation except for gender where 70% of the rabbits with acquired dental disease were male. She concluded that Metabolic Bone Disease plays a major role in the development of dental disease in pet rabbits.

Metabolic Bone Disease: What does this mean?

I know that low-calcium diets have been popular for pet rabbits, guinea pigs, and chinchillas because of the fear of urinary sludge and stones (calcium is not the problem). This trend is likely the cause of much of the dental disease in the pet population today. I highly recommend a balanced diet that is higher in calcium (stay away from vitamin D3 though!!!) and make sure your pets get regular dental check ups to identify any dental problems so they can be treated before they get worse. Also be aware that clipping your pets front incisors greatly increases the risk that they will become maloccluded. It is far better to have the ground down with the proper equipment. If you have to have your pets incisors modified due to malocllusion be aware that it will increase the rate in which they grow so they will have to be adjusted regularly. Ask your vet about grinding the teeth instead of clipping them. This minimizes any stress that might cause the teeth to become crooked.

Genetic or Nutritional?

Malocclusion is a very serious condition that needs regular veterinarian care (modification of the teeth) or it could cause anorexia and eventual starvation as the incisors grow too long to allow your pet to eat or the cheek teeth develop spurs that cause abscesses. Some pets are more prone to this condition than others. It is most likely due to dietary mineral imbalances or Hyperparathyroidism (unbalanced diet-induced metabolic disorder). A properly balanced diet goes a long way at preventing these issues for all pets.

Say NO to Wire Cages

There are other causes of malocclusion. Sometimes when rabbits, guinea pigs or chinchillas are kept in a wire cage they will chew on it and damage their teeth leading to a mechanically induced malocclusion. In either case pets with miss-aligned teeth must have them regularly trimmed.

Works Cited

Jacqueline Müller, Marcus Clauss, Daryl Codron, Ellen Schulz, Jürgen Hummel, Mikael Fortelius, Patrick Kircher, and Jean‐Michel Hatt 2014. Growth and Wear of Incisor and Cheek Teeth in Domestic Rabbits (Oryctolagus cuniculus) Fed Diets of Different Abrasiveness. J. Exp. Zool. 321A:283–298

A. L. Meredith, J. L. Prebble and D. J. Shaw 2015. Impact of diet on incisor growth and attrition and the development of dental disease in pet rabbits. Journal of Small Animal Practice 56, 377–382

S.A Norris, J.M Pettifor, D.A Gray, R Buffenstein 2001. Calcium metabolism and bone mass in female rabbits during skeletal maturation: effects of dietary calcium intake. Bone 29:62–69

Frances Margaret Harcourt-Brown 2006. METABOLIC BONE DISEASE AS A POSSIBLE CAUSE OF DENTAL DISEASE IN PET RABBITS. Thesis published online

R. J. Bindels, A. Hartog, S. L. Abrahamse, C. H. Van Os 1994. Effects of pH on apical calcium entry and active calcium transport in rabbit cortical collecting system. American Journal of Physiology 266: F620-F627

Premium Foods

Scientifically balanced to optimize long-term health by minimizing protein waste / litter box odor / urinary sludge, supporting proper digestive health, and maintaining a healthy weight. As a result you’ll also notice softer fur and an increase in energy
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Should You Be Feeding Pellets Made With Alfalfa?

Sherwood formulas use alfalfa & timothy instead of soy and grain because rabbits and other small herbivores are adapted to a diet that is a mix of grasses (like timothy) and legumes (like clover or alfalfa). This style of a diet provides a better balanced higher quality source of protein and fiber than grain and soy based diets. This reduces protein waste and greatly reduces the risk for the most common health problems plaguing small herbivore pets (digestive and urinary).

Just how much timothy is in your brand?

Most brands that list timothy hay as the first ingredient rely on soy and grain by-products to provide protein/energy. These foods are actually loaded with a larger amount of combined soy and grain by-products (soybean hulls, soybean meal, wheat middlings) than the total amount of hay.

Popular National Brands “Timothy Pellets”

(Grain and Soy Based)

SHERWOOD Timothy and Alfalfa Blend Pellets

(Hay Based)

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SARx (pronounced SAR-ex) are multi-step premium rescue and recovery products designed specifically for each species (Rabbits, Guinea Pigs, and Chinchillas).
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SARx Recovery product is a scientifically balanced complete meal (grain/soy-free) with an extra nutritional boost designed to help stressed pets make a great recovery.

Each formula is specifically formulated for each species (PLUS formula is for weight gain).

How it works: After an operation or other stressful event some small animals may be too weak to eat. These same pets will have an increased need for specialized nutrition to compensate for disrupted metabolic cycles and caecal fermentation patterns until they are re-established. If needed provide the SARx Rescue product which restores nutrients needed to stimulate the appetite.

How it is administered: This specially formulated balanced and complete food is to be mixed with warm water in a 1:3 ratio (1 tablespoon recovery food mixed with 3 tablespoons water), then slowly mouth feed with the provided syringe.

After an operation or other stressful event we recommend feeding the SARx Recovery a minimum of 3 times a day until your pet starts eating normal amounts of dry food (hay and pellets). In most cases this will be less than 3 days but in some cases it could take up to 8 to 10 days.

For some degenerative health conditions the SARx formula can be fed regularly to supplement or replace the normal diet. It contains an extra dose of proper long-stranded fragments of timothy hay to compensate for bunnies who do not or cannot eat loose hay. It also provides motility herbs (found in our digestive tablet) that help regulate healthy ceacal fermentation patterns (very effective at preventing G.I. stasis).

Species Specific Nutrition: Instead of providing a single generic formula for all small herbivores, it is very important to tailor the formulas to provide optimized species-specific nutrition. Additionally Sarx Recovery is available in two formulas for each species depending upon body condition (PLUS is for weight gain). You can easily switch between formulas or blend them as needed.

Maintaining a healthy weight for small herbivores who are already at a healthy weight or need to lose weight.

For small herbivores who need to quickly gain more healthy weight.

SARx Rescue product is a scientifically formulated quick acting water soluble nutrient mix that quickly regenerates your pets feeling of well being and stimulates their appetite providing a jump-start to a good recovery.

How it works: Small animals that have quit eating and/or drinking are hours away from dying. There are many causes of such a condition (stress, improper diet, dehydration, surgery, and others). In any of these conditions the main cause leading to the refusal to eat/drink is a lack of specific nutrients in the blood stream that normally signal to the brain the current metabolic status of the animal and regulate the appetite. Restoring these nutrients is key to stimulating the appetite and starting your pet back on the path to recovery.

How it is administered: The SARx rescue product comes as a powder in a sealed bag (foil lined to exclude light). To use simply mix the powder in water and draw up into a syringe (1 scoop of powder per 3cc water per pound of body weight) and then mouth feed. The ‘fiber-free’ pre-dissolved nutrients ensures a fast acting delivery system that is very quickly absorbed into the blood stream. The powder has a subtle salty taste to it and is flavored with organic banana.

Repeated use?: In some cases it may be necessary to provide the stressed small herbivore with additional doses. In such a case it is advisable to give the first dose in the full amount. Then, ideally, within 30 minutes or less of administering the SARx rescue product the patient should be encouraged to start eating SARx recovery food. If the patient still isn’t eating then 2nd SARx rescue dose can be administered in the full amount. Additional doses can be given every 4 hours at a half rate (½ scoop/lb. body weight) as needed but it is critical that the patient begins to to eat the SARx recovery food.

Contact your local small animal veterinarian for additional professional care. If they are not yet aware of SARx, call us to send them samples and additional technical & formula information.

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Support Tablets

Customized Nutritional Suppport for Special Needs Pets
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Active Ingredients: Triple Berry Blend (Blue Berry, Maqui Berry, Acai Berry), Banana, L-Ascorbic acid (Vitamin C), Citrus Bioflavonoids.

Inactive Ingredients: Cellulose

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A balanced diet is also crucial to preventing sludge/stones. Read PDF on Urinary Health.

Active Ingredients: Cranberry, Magnesium Sulfate, Banana, Marshmallow Root, L-Ascrobic Acid (vitamin C), Magnesium Stearate, Pyridoxine hydrochloride (vitamin B6).

Inactive Ingredient: Cellulose

If you have a pet with a special need please Contact Us so we can discuss their health concerns and see if they are a candidate for a free sample.

Papaya: Ripe papaya provides a dose of digestive enzymes and phytonutrients.

Cellulose: Pre-biotic that support the growth of healthy bacteria in the ceacum.

Banana: A great natural flavor loved by pets.

Bromelain and Papain: Additional protein digestive enzymes from pineapple and papaya used to minimize protein load on the ceacum.

Ginger, Ginseng, and Szechuan peppercorns: This blend of herbs stimulate phasic muscle contractions in the lower G.I. tract to support optimal ceacal fermentation patterns. This helps older and less-active small herbivores to properly ferment their food (including megacolon rabbits currently under trials – see below).

B-Vitamin Complex: These are normally produced by optimal ceacal fermentation patterns. Supplementation is often needed to help maintain a healthy appetite during digestive upset. It really works!

Vitamin C: The majority of the immune system is hard at work in the lower G.I. tract. During digestive upset it is beneficial to supplement with vitamin C. We use shelf-stable vitamin C that is coated in cellulose fiber to exclude oxygen.

Megacolon (actually a ceacal motility disorder that leads to ceacal impaction) is an extreme case requiring digestive support to maintain life. It is a genetic disease that breeders selected for because they were selecting for a specific color pattern. Sadly as a result many rabbits world wide suffer from a genetic defect with horrible consequences.

Currently there is a documented genetic cause for megacolon. It is the same gene that leads to the distinctive color pattern (can be any color – the pattern is the most diagnostic) where fewer spots means the worse the condition. Essentially the gene that is affected is (the expression levels of) a trans-membrane receptor protein that signals the migration of neurons during early development (in utero). The net result is that rabbits that have this gene have less innervation of the lower digestive tract. Without the nerves to stimulate muscle contraction the rabbit cannot regulate proper ceacal fermentation patterns which often results in uneaten ceacotrophes. Consequently B-vitamin levels drop and so does the appetite. Without motility drugs rabbits also become ‘constipated’. All of these issues add up to a high mortality rate especially as the digestive system increases in size and as the afflicted rabbits age and become less active (younger rabbits have less of a problem).

The severity of this condition varies from pet to pet. One direct cause of this variation is the number of ‘megacolon’ genes that are carried (0, 1, or 2). Other factors such as age, size, and the extent of damage caused by previous ‘episodes’ of stasis suffered by the rabbit also greatly influence the current condition. The life of the megacolon rabbit becomes dependent on motility drugs and other special care.

There is no cure for this genetic disease. However, proper nutrition, exercise and veterinary care (including motility drugs) can work ‘miracles’ for many of these bunnies. Our digestive tablet is a simplified solution that can be included as one of these miracles for megacolon rabbits and other bunnies that suffer from weak digestion due to age, inactivity, and other reasons.

The digestive support tablet works in 3 very specific ways.

First, the digestive tablet is based on papaya. The papaya aids in protein digestion which minimizes the amount of protein that will enter the ceacum where bacterial fermentation of fiber occurs. Too much protein in the ceacum will raise the pH and support the rapid growth of unhealthy bacterial populations that cause bloat, G.I. stasis or other digestive problems.

Second, it provides a full compliment of B-vitamins that are normally produced by healthy fermentation patterns. If these fermentation patterns are disrupted then B-vitamin production is reduced and this often leads to a loss of appetite and reduced energy levels. Proper levels of B-vitamins are necessary to maintain a healthy appetite.

Third, it contains a unique blend of herbs that actually stimulate the lower digestive tract to naturally contract and relax in a rhythmic pattern to help optimize healthy fermentation patterns by mixing ceacal contents. For rabbits that are less mobile (don’t get enough exercise due to age or arthritis) or that simply have trouble with digestion (especially megacolon rabbits who lack the lower G.I. tract innervation necessary to stimulate muscle contraction) this blend of herbs MAY replace the need for the use of motility drugs though this needs to be determined on a case by case basis. The herbs have been shown to directly trigger rhythmic muscle contraction/relaxation in lower rabbit digestive tract independent of nerve stimulation… and it works!!! See our reviews!

If you have a rabbit with megacolon please contact us so we can get you some free samples. The tablets are about a 1/2 gram in size. They are to be fed like a treat at the rate of one tablet per pound of body weight per day divided into a morning and evening feeding (for example, a 4 pound rabbit would eat 2 tablets in the morning and 2 tablets in the evening). NO OTHER DIETARY CHANGES ARE NEEDED as long as they are on a hay-based diet (we recommend to eliminate sources of grain and soy from the diet). We can then work with your veterinarian to safely assess the progress your bunny is making. The ultimate goal is to reduce or eliminate the need for motility drugs in the majority of the cases but we advise against doing so until your veterinarian clears it.

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Superfood Blend: Our custom blend contains Kale, Acai Berries, Carrot, Apricot, Kelp, Spirulina, and Red Bell Pepper. We chose these because they provide a rich blend of diverse phytonutrients with many immune supporting properties.

Turmeric: Contains high levels of curcumin, which is a potent anti-inflammatory and antioxidant.

Ginger: Ginger is a strong antioxidant, anti-inflammatory, and antimicrobial, antiviral. It also contains many compounds that are anti-tumor and anti-cancer. It improves circulation and is a great cleanser.

Ginseng: Ginseng plays an important roll in regulating various types of immune cells. It is also effective at controlling inflammatory diseases and microbial infections.

Astragalus Root: Astragalus root helps improve the immune response to fight infection.

Vitamin C: It is beneficial to supplement with vitamin C when trying to reduce inflammation. We use shelf-stable vitamin C that is coated in cellulose fiber to exclude oxygen.

If you have a pet with a special need please Contact Us so we can discuss their health concerns and see if they are a candidate for a free sample.

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Turmeric: Contains high levels of curcumin, which is a potent anti-inflammatory and antioxidant shown specifically to improve joint health.

Glucosamine: Oral glucosamine is effective at helping to rebuild cartilage by preventing localized deficiencies that would otherwise inhibit repair.

Chondriton Sulfate: Reduces the concentration of the pro-inflammatory molecules in the joint and decreases the impact of atherosclerosis and chronic arthritis and reduces synovitis.

Methysufonylmethane (MSM): MSM is a major building block of joints and when supplemented it can increase the concentration needed to stimulate repair. It is best when used in combination with chondriton sulfate, glucosamine, and anti-inflammatory agents.

Vitamin C: It is beneficial to supplement with vitamin C when trying to reduce inflammation. We use shelf-stable vitamin C that is coated in cellulose fiber to exclude oxygen.

Why Carrots?: Carrots provide diverse antioxidant support. They also make a great flavor combination that makes turmeric more tolerable by our pets (based on our own testing). In this case a ‘spoon full of carrots help the medicine go down.”

If you have a pet with a special need please Contact Us so we can discuss their health concerns and see if they are a candidate for a free sample.

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