Since it was not eaten, I am guessing a dog.Not many predators will leave an easy meal unless your dog ran it off. Number two is a hawk absolutely can not fly away with a 5 lb Chicken period! Even an Golden or Bald eagle. They eat their kill at the scene. Horned Owl is the only North American raptor that can carry a chicken off the ground and that is only for a hundred yards or so. I know there are some who claim to have seen Redtails Hawks carry off 5 lb plus Rhode Island Reds. Must have been a dream. There is a reason you can 't find a photo anywhere of a hawk flying with a full grown Chicken.