Dietary changes can also cause upsets, so any new foods should be introduced gradually. If you are changing the diet, begin by mixing a small amount of the new food with the older food, and gradually increase the proportion of the new food. Also, treats must be limited to very small quantities to avoid upset.
Choosing a Chinchilla Food
I recommend a pelleted diet over loose. Loose mixes may be nutritionally balanced, but only if the chinchilla eats all the components of the diet (and chinchillas are prone to picking out what they like from a mix).
Look for a pellet formulated specifically for chinchillas that is 16-20 percent protein, 2-5 percent fat and in the range 15-35 percent fiber1. If it is impossible for you to get a good quality chinchilla diet, many experts suggest substituting a good rabbit or guinea pig pellet with similar characteristics.
Most chinchillas will eat one to two tablespoons of pellets a day. While they are not prone to overeating, for freshness it is a good idea to feed a small amount of pellets at a time. Feeding a tablespoon (per chinhcilla) in the morning and again in the evening (times when chichillas are most likely to eat) seems to work well, but can be adjusted if needed. Some people just feed a couple of tablespoons in the evening. Try to be consistent whatever you choose to do, as chinchillas like routine.
A small food hopper or heavy ceramic dish is the best way to keep the food from getting dumped or soiled.
A note about corn: the topic of corn in chinchilla diets is controversial. There is concern that feeding corn can cause digestive upset and bloating, but many chinchilla foods contain corn as an ingredient. Scientifically speaking, little is understood about the ideal chinchilla diet beyond the need for lots of roughage, but since corn is starchy and likely largely indigestible for chinchillas, I'd avoid whole corn as a treat or the main part of a diet. It can be hard to avoid corn (ground corn, corn meal) in pellets, but I'd advise looking for a diet where corn is listed far down the list of ingredients, if at all. Diets such as Oxbow's Chinchilla Deluxe or Mazuri's Chinchilla diet are considered among the best pellets (at least in North America; other good quality brands may be available in other areas).
Give Fresh Hay Daily
Even when you choose a high fiber diet, the a pelleted diet must still be supplemented with hay (see below) to ensure your chinchilla gets plenty of roughage for the proper functioning of the digestive system. The roughage in hay also helps with keeping the teeth in good condition.
Feed as much good quality hay as your chinchilla wants each day. Hay should be cleaned out and fed fresh on a daily basis to keep it from becoming soiled or moldy.
Pressed cubes of hay can be given, though I suggest also feeding some loose hay, as it has more long strand fiber (and chinchillas seem to enjoy playing with it, too). Alfalfa hay should not be fed exclusively to most adult chinchillas; alfalfa is high in protein, calcium, and oxalates, and too much could possibly lead to urinary and other problems (it is good for growth, breeding chinchillas, and as a treat). Timothy hay and other grass hays are excellent sources of roughage, and should make up the bulk of the hay fed to adult chinchillas. Don't feed any hay that is damp, smells musty, or is discolored.
Treats for Chinchillas
Chinchillas should be given very little in the way of extra treats -- never more than a teaspoon a day. Raisins and dried fruit are favorites, but high in sugar so should be fed in very small quantities, and infrequently. I do recommended using raisins as treats for taming chinchillas, but you can make a raisin go a long way by cutting it into several small pieces. Try not to feed more that 3 or 4 raisins per week. Rose hips are another recommended treat as they are high in vitamin C and other nutrients (check your health food store). Most commercial treats for chinchillas will be too high and sugar and fat and are best avoided. There is much conflicting advice about what sort of treats are okay; check with your vet if you are unsure about anything you are feeding your chinchilla.
Though we don't normally think of twigs and branches as anything special, your chinchilla will likely view them as a terrific treat. Twigs from apple trees and other safe trees can be given to your chinchilla. Make sure any wood you use has not been treated with pesticides, and do not give branches from toxic trees, including trees fruit has pits or stones, evergreen wood, and others -- for more information see this article about safe and toxic woods for chinchillas.
Coprophagy - Is My Chinchilla Eating Poop?
Yes, your chinchilla may eat it feces. This is an adaptation of several herbivorous animals that eat a high fiber diet (such as rabbits). They will ingest a special type of soft feces as they defecate, different from the normal dry feces deposited on the ground. This is important to proper digestive function and nutrition, so don't worry if you see your chinchilla doing this. 1 Hillyer, E. and Queensbury, E. "Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery." W.B. Saunders, 1997.