The single most important thing you can do for your rabbit is feed it hay. Hay is an essential part of the rabbit's diet. Hay is a dried plant product, such as a grass or legume, which is fed to animals. Examples of grass hays are timothy, brome, orchard, and oat grass.
Legumes contain more protein and calcium than grass.
Examples of legume hays are alfalfa and clover. As hay matures, the amount of protein decreases while the fiber increases. However, both types of fiber serve a purpose in the digestive system of a rabbit. Many animals require fiber in their diet to stay healthy. Without adequate amounts of fiber, illnesses such as gut stasis and enteritis can occur.