After an owl or hawk eats his meal, it spits up a pellet. Owls do not digest the bones of their meal, so in an owl pellet, you will always find, hair and bones. Hawks digest the bones, so in a hawk pellet you only find fur. Sometimes in our rat order, we get hairless rats. After the hawks ate the hairless rats, one of the keepers noticed that there were no pellets to pick up. No hair on prey = no hawk pellet!