Chinchillas eat an alfalfa based pellet. It is different from guinea pig and rabbit pellets as it is higher in fiber, protein and calcium. Always have fresh water in a bottle daily.
An average adult will eat approximately 1-2 tablespoons per day, along with alfalfa hay and/or timothy hay. A mineral block (without salt) and a cuttlebone is a good source of calcium. Supplements can be given such as Manna, Sweet Feed and Vita Grain up to 3 to 4 times a week, as a treat or training tool. Other treats should be given sparingly. They include such things as dried raisins, banana chips, papaya, pineapple, cranberry, sunflower seeds, pumpkin seeds, peanuts, (in the shell and unsalted). Avoid Fresh fruits and vegetables because of the water content. Too much of a good thing results in diarrhea and/or constipation.
Their feces are always a good indicator that you are not loving them too much. Sticking to a balanced diet will keep your pet healthy.