Has anyone ever put a kitten together with an apple and a rabbit, just to see which one it eats/plays with?

I think this would make more sense to say "a 3 year old" , but not a baby. A baby wouldn't eat the apple because they don't have teeth, and when they do get teeth, they're still very weak and can break if they bite into an apple. I do get where you're coming from though. It would make sense that a child would eat an apple over that live rabbit, and that cat would be the one to eat it.