Sounds like a raccoon or a weasel. What area of the country do you live in? And what time of day did you find your hen dead? So sorry for the news. Its heartbreaking. We just lost one of ours to a fox. Was she by chance laying close to the outer area of her pen? Birds will grab her and take her away, leaving little behind so definitely wasn't a hawk or owl. Sounds most like a weasel. They take in innerds out, chew off the rear ends and the backs of their heads and neck and then leave the rest. Go to the store and get the September/October edition of Chickens magazine from Hobby Farms. They have a great, large and in depth article about figuring out which predator got to your birds, based upon what you have found left behind. You can also go to chickensmagazine.com and probably find the article. Sorry for your news