I am no expert on rabbits by any means but following speaking at a nutrition debate at Cambridge University organised by the Association of Veterinary Students in November 2007, I learned the following from an excellent speech (top speaker of the day IMHO) by Cambridge University vet Tom Harcourt-Brown MRCVS. I include this page for informational purposes for rabbit owners and to demonstrate the lengths to which the pet food manufacturers will go to sell their products regardless of the impact on animal health. You can download by saving then listen to Tom's speech by clicking on the MP3 logo in the left column lower down the page.
Rabbits are designed to eat a relatively large quantity of poor quality fibrous food. It is for this reason that rabbits are coprophagic - ie they eat their green droppings produced when food passes through the digestive tract for the first time. They will then double-digest their food and produce the harder brown rabbit droppings we commonly see when walking our dogs in the countryside.
Rabbits are not designed to eat grain-based feeds as it is too rich from being nutrient-dense. Rabbit feeds produced as a mix (ie not pelleted) allow the rabbit to pick out the low grade fibrous elements, leaving the more nutrient-rich elements which contain those nutrients put back chemically to replace those destroyed by the original manufacturing process. This is researched fact that rabbits do this.
The alternative is to pellet all the ingredients together so that rabbits cannot pick and choose. The problem with this is that the resultant pellet is nutritionally too high quality and rabbits will tend to over-eat in order to get satisfaction from a stomach-fill volume perspective. This means they tend to get too fat. This is researched fact.
Both scenarios will inevitably result in dietary-related rabbit diseases which from what I could gather from Tom Harcourt-Brown MRCVS makes up the vast majority of rabbit cases he sees in veterinary practice.
The rabbit skull on the left is that of a wild adult rabbit. See how the wild diet consisting primarily of grass has kept the front incisors at a functional length. The rabbit skull on the right is that of a pet bunny fed on commercial feed with inadequate roughage. Notice the gross over-growth of the front incisor teeth which prevent them from being functional.
To be fair, the commercial rabbit food manufacturers have recognised this and so label the bags as not being suitable as a sole nutritional source. However this is usually hidden away in small print so that it is unlikely that many rabbit owners are aware of this being on the bag. Of course if the rabbit food manufacturers had the best health of rabbits at heart they wouldn't produce any commercial rabbit feed at all. If you think I'm being paranoid about the intentions of the manufacturers it might persuade you otherwise to know that the Pet Food Manufacturers Association tried to suppress the rabbit nutrition issue at the Cambridge debate, presumably so that the students as the future veterinary profession would not become aware of these issues. Now who's interests do you think they really have at heart?
So what is recommended as the ideal rabbit food I hear you ask? Well there are no surprises for guessing that it's grass and other vegetation that can easily be picked for free on a daily basis. Even in cities there are parks and gardens that can be used as a source.
I don't know about other small furry rodents etc but I suggest you do your own research from an unbiased source. Don't rely 100% on your local Vets as they might not have been given the full picture either and don't have sufficient time to research every piece of information they are continually fed by reps. We are human after all!!