Rabbits have complex digestive systems, so it's very important that they receive a proper diet. Many health problems in rabbits are caused by foods that are incompatible with their digestive physiology. A basic rabbit diet should consist of the following foods:
Rabbits need hay—specifically, Timothy grass hay. Rabbits should have access to a constant supply of this hay, which aids their digestive systems and provides the necessary fiber to help prevent health problems such as hair balls, diarrhea, and obesity. Alfalfa hay, on the other hand, should only be given to adult rabbits in very limited quantities, if at all, because it's high in protein, calcium, and calories. Vegetables
In addition to hay, the basic diet of an adult rabbit should consist of leafy, dark green vegetables such as romaine and leaf lettuces, parsley, cilantro, collard greens, arugula, escarole, endive, dandelion greens, and others. Variety is important, so feed your rabbit three different vegetables at a time. When introducing new veggies to a rabbit's diet, try just one at a time and keep quantities limited.
Fruits and Treats
While hay and vegetables are the basis of a healthy diet, rabbits also enjoy treats. Cartoons and other fictional portrayals of rabbits would lead us to believe that carrots are the basis of a healthy rabbit diet. Many rabbits enjoy carrots, but they are a starchy vegetable and should only be given sparingly as a treat. Other treats your rabbit might enjoy are apples (without stems or seeds), blueberries, papaya, strawberries, pears, peaches, plums, or melon. Extra-sugary fruits like bananas, grapes, and raisins are good too, but should be given on a more limited basis.
Foods to Avoid
With such sensitive digestive systems, there are a number of foods that rabbits should avoid eating. These include iceberg lettuce, tomatoes, cabbage, corn, beans, peas, potatoes, beets, onions, rhubarb, bamboo, seeds, grains, and many others. Also, don't feed your rabbit chocolate, candy, anything moldy, or most human foods. If you are not sure about a certain food, ask your rabbit's veterinarian.
If you choose to make pellets a part of your rabbit's diet, it is best to use them as a supplement to the dark green, leafy vegetables, not as a substitute. These pellets should only be given in small quantities (1/8 -1/4 cup per five pounds of body weight per day, spread out over two daily feedings). Also, make sure to purchase Timothy-based pellets. Many brands of rabbit feed contain seeds, corn, and other foods that are too high in calories to be the basis for a healthy rabbit's diet.
Rabbits should always have an ample supply of fresh water available. Be sure to change your rabbit's water at least once each day. Water can be kept in a sipper bottle or bowl. If you use a sipper bottle, watch new rabbits to make sure they know how to use the bottles, and clean bottles daily so the tubes don't get clogged. If you use a bowl, make sure that the bowl is heavy enough to avoid tipping and spilling.