We have a secure coop and a run with a chicken wire roof and the wire buried all around. There are no signs of digging or tears in the wire. Yet one of our young buff orpingtons was found with its head torn off. No other damage to the chicken, and no sign of the head. The chicken wire has two-inch openings; could something small enough to get through that opening have caught and decapitated one of my young birds? I also have some older hens in the run; one of them couldn't (wouldn't) have done this, would it? Anybody have any idea what might have done this?