Instead of cow's milk, use KMR (Kitten Milk Replacer) or Goat's milk. When you give goat's milk be sure it is warm.
Rabbits are in a class by themselves. They need a pinch of acidophilus powder to digest their formula and lactate will also have to be added.
If a baby rabbit's eyes are closed, he or she is very young and will have to have formula twice or three times a day. You can use KMR - Kitten Milk Replacer. Give them the formula with a 1cc syringe fitted with a cattak (photo, upper-left).
When they are older, you can use a jar top for a mixture of baby garden vegetables, squash and spinach. Bunnies will use a litter box, so be sure to put one into their cage.
For older bunnies, pick dandelions and clover, use a spray bottle with water to spray the greens because rabbits shouldn't have water and that will provide moisture. You can put grass in with the mixture and the next day it will all be eaten. Rabbits love it. Also, if you can get it, feed grass hay species such as Timothy - if you're not near a farm, pet stores package hay. Alfalfa is considered to be too rich, but it will do in a pinch.