First things first, I will inform you about the history of pellets - so far I only managed to find information about the history of rabbit pellets (though I assume it will be similar for guinea pigs also). Rabbit pellets were developed around 1953 for industrial farming, so the intended use of pellets was to create an easy and cheap alternative to the natural foods (grasses, herbs, branches) which they should ideally be consuming. Pellets are now also used for pet ownership, and have been fed for many years, but do they really require pellets in their diet?


In nature, the diet of the wild ancestors of our domesticated rabbits & guinea pigs consists of grasses, herbs, bark, leaves & twigs - plus the occasional leaves of vegetables. Despite the fact that rabbits & guinea pigs look very different to their wild relatives, their digestive system still works the same way.


Commercial pellets often come in colourful eye catching packaging. The reality is that if people stopped purchasing these commercial dried pellets/mueslis, then thousands of sales and money would be lost buy these industries, hence why they claim to make all these promises with the food they supply, but is this really true? Lets take a closer look at the impact pellets can have on rabbits and guinea pigs.


Not all, but some pellet brands absorb water, and as a result they swell in the guinea pigs & rabbits stomach.

I conducted a mini experiment to demonstrate this:










After just 5 minutes, the pellets had absorbed a large amount of water.

This makes the pellets useful for syringe feeding as they are a better consistency for that.

However, too many pellets which swell at one time could be harmful.




Even pellets that do not swell can be harmful. Pellets are a very concentrated feed and as a result, they slow down digestion. Pellets that are heat pressed lose vitamins due to the high temperatures during the manufacturing process. As a result of the vitamins being lost, artificial vitamins are added to ‘replace’ what was lost during the process, often too many artificial vitamins are added and this can be harmful. 


Contrary to popular belief, pellets do not keep their teeth trimmed - this is because they are not fibrous enough, unlike the natural grinding motion they would do when consuming things like hay, grass, plants and leafy greens. Too many pellets can leave guinea pigs & rabbits feeling full, and as a result they will not eat as much hay and other abrasive food (which does contribute to the abrasion of their teeth). Rabbits and guinea pigs have a thin stomach and a long intestine (which does not have peristalsis), therefore if they do not eat for long periods of time, everything stops moving.

Because pellets are so dry and they absorb water in the stomach, healthy bladder and kidneys are no longer guaranteed (because of the lack of water) so there is a higher risk of bladder and kidney related problems, such as the formation of stones. Also, if they eat too many pellets, they may not eat as much fresh food containing plenty of fluid. Fresh grasses, plants and vegetables are all important for ensuring they are receiving plenty of fluid to keep them hydrated and healthy. Pellets are generally composed with various grasses, meadow plants and herbs - in the fresh form it is the healthiest food for guinea pigs and rabbits and is what nature intended. The calcium content is not a problem due to the high water content (excess calcium is excreted during urination), however when this is in the dried form and pressed into pellets, the calcium content combined with lack of water promotes kidney and bladder problems.


guinea pig pellets

Are all pellets bad?

Some are much better than others. It is important to know what to look out for and what to avoid. There are so many brands available on the market, some good, some bad. It is important to do lots of research into the type of pellets you feed to ensure they are healthy. It is certainly possible to feed a pellet free diet all year round and I would reccomend this above feeding pellets. Some guinea pigs and rabbits are prone to developing stones, therefore owners often feed a very small portion, if not remove them completely from the diet. For guinea pigs and rabbits, about 1 tbsp/kg daily (about 15g or 1/8 cup) at the very most. Remember that pellets are a concentrated feed and high in energy, so they are only a supplement to the daily diet. You should weigh the animal weekly to ensure they are maintaining a healthy weight with the diet you feed. Always ensure they have fresh water available! A bottle/bowl next to the pellet bowl is a good idea.

grain free?

Quinoa, millet & buckwheat are all gluten free, so are better tolerated. On the other hand, grains such as wheat and rye and not easily digested and are therefore unsuitable. I visited various pet shops, looking at the ingredients in different pellet brands. I was surprised to see how many contained wheat, some even as the top ingredient! I decided to research further and in doing so, I discovered that pellets that have been through the extrusion process are easier to digest because the grain becomes denatured. However, the high temperatures of this process means that natural vitamins & goodness are lost in manufacturing, and as a result the manufacturers generally add artificial vitamins to compensate for the natural vitamins being lost.

cold pressed?

Cold pressed pellets retain many of the natural vitamins, ingredients and nutrients due to the low temperatures during the manufacturing process. This means that usually no artificial vitamins and so fourth are added as a result.

best pellet brand?

The best pellets to feed are grain free, cold pressed pellets with no artificial ingredients added. The pellets should not contain any sugar, honey, molasses. Molasses is a waste product from the sugar industry often used to combine the ingredients. An estimated 50% of molasses contains sucrose which has been known to damage their intestinal flora. This ingredient also favours e.coli so is best avoided. The ingredients should mainly consist of meadow plants to mimic their natural diet. The pellets should be low in energy and fat. Oil seeds are a healthy addition to pellets to ensure they are supplied with the necessary fatty acids. My personal favourite pellet brand is Rosewood Meadow Menu.

guinea pig pellets
guinea pig pellets


  • 100% natural (over 40 ingredients - all healthy!)

  • Timothy based

  • Cold pressed

  • High fibre 

  • Beneficial seeds (for digestion & fatty acids)

  • Ideal Ca:Ph ratio (for pellets..)

  • Grain free

  • Low energy

beneficial ingredients 

swell test

I decided to test these pellets for swelling, so I took 5 pellets and poured water over them.

These are the results:

After just 5 minutes, the ingredients in the pellets started to separate.  

guinea pig pellets

After 1 hour, almost all the ingredients had separated. 

guinea pig pellets


guinea pig pellets

The results from this experiment show that these pellets do not swell as much as other popular pellet brands - in fact the ingredients break apart so they are easier for guinea pigs and rabbits to digest. However, all pellets slow down digestion to an extent. The image towards the left shows the remains of the pellets after draining out the water. You can see only a small amount of the original pellets were still breaking apart. This brand is definitely one of the best, though pellets are still pellets and in nature they would not be consuming concentrated ingredients pressed into pellets. There are still health problems associated with feeding pellets (dental, bladder, kidney, digestive and even fresh food inolerances) despite being made from natural ingredients. A pellet free diet is definitely healthiest, but if you wish to feed pellets, this is the brand I highly reccomend.

click on the images below to learn more about each type of dried food


1. Cold pressed, grain-free pellets are the best option out of all pellets available on the market. They retain natural vitamins and minerals and the swelling is not as bad as with other types. They generally have a very natural composition with various grasses, meadow plants and herbs.

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2. Generally muesli style food contains many unhealthy ingredients. They have a high proportion of fatty ingredients, which can lead to animals becoming overweight. Dental problems are also associated with this style of food. It is common for a large amount of additives to be added, which is of course unhealthy.

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3. These pellets are heated to a very high temperature to make the grain easier to digest, however the natural nutrients are stripped due to the temperatures at which they are heated. As a result, manufacturers tend to add artificial vitamins and minerals which are harmful. Additives are also commonly added to this style of food. These pellets are also very high swelling.

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4. This style of food in theory is most natural. Those available on the market usually have a natural composition, however 'bulking agents' are often added in the form of pellets that commonly contain molasses, which is unhealthy for rabbits and guinea pigs. A homemade version of this would be much more suitable.

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