The bulk of a rabbits balanced diet consists of fresh Hay (or grass) and should always be available. This is the most important part of a rabbit’s diet.
Young bunnies should be exposed to hay as soon as they can eat on their own. This is easiest with outdoor rabbits kept in larger free-roaming pens.
Mixed grass (timothy, meadow, oat, rye, barley or Bermuda grasses) hay is lower in calcium and calories.
Alfalfa (and clover, peas, beans or peanut) is not recommended. 

Green foods are the next most important food in the rabbit’s diet. Feed your rabbit leafy green vegetables daily for a balanced diet. Smaller amounts at first, and as the bunny adjusts to this diet more can be fed. Greens are an important addition to the diet, but should never be the total diet.
Greens consist of Broccoli, Brussel sprouts, Cabbage, Carrot/beet tops, Celery, Kale, Leaf lettuce ect 

Foods to avoid
Avoid starchy foods or high sugar content foods such as; legumes, beans, peas, corn, bananas, grapes, oats, wheat, crackers, chips, bread, nuts, pasta, potatoes, chocolate, cookies, rolled oats and breakfast cereals, beans (of any kind), breads, cereals, corn, refined sugar and seeds.

Treat Foods
Apples, berrie, Carrots, bell peppers, Melons, Peach, Pear, Pineapple, Squash 
Since these treat foods do not contain the nutrients for a balanced diet, we recommend feeding these foods in limited quantities. Just like humans and treats, some rabbits like these foods so well that they will eat them to the exclusion of all others, thereby creating a potential for health problems. 
Foods from this list can be fed daily and you may even wish to use them for training rewards.

Ensure rabbits have plenty of fresh clean water that is changed often. Change the water completely and clean the water container at least weekly.