Vegetables are extremely important in a rabbit's diet. When shopping for rabbit vegetables, look for a wide variety. Both dark, leafy vegetables and root vegetables are important. Look for different colors, and stay away from beans and rhubarb. Vegetables should be thoroughly washed to remove dirt and insects.
If you feed your rabbit a lower amount of pellets than what is noted here, you must replace the nutritional value without the calories. Increasing the amount of vegetables fed does this. Also, a variety of hay must be encouraged all day long, which is done by offering fresh hay and straw a couple of times a day. See your veterinarian if you think that you should do this for your rabbit.
Rabbits must eat at all times of the day; therefore, you must always have hay, water, and vegetables available. There is no maximum amount of vegetables that should be fed. If your rabbit eats all of his pellets for the day, do not feed more. Instead, feed more vegetables. Many veterinarians will say to fast your rabbit before surgery. This is not a good idea, and you should tell your veterinarian why. If rabbits do not eat constantly, their digestive system will not work properly. Rabbits are incapable of vomiting, which is why hairballs are a problem.
Click here to find out what to feed your rabbit at different ages, and here for a list of safe foods!