I think you need to be more clear on what you are asking here. Are you asking what to feed a baby rabbit or what to feed a new born kitten? What exactly is it you need to know how to feed and why? You haven't given us any details about the situation, so it's impossible for us to make any sort of recommendations or help in any way. If it is a baby rabbit, where did it come from, is it's mother around, and is she feeding it, and how old is it?