I'll second or third racoonies. Whenever we get a hawk issue they look like they've been blown up. Feathers everywhere, usually at ten - twenty foot increments of feather piles in whatever direction they've taken them. It takes a bit of effort to keep a grip on something struggling and fly and they seem to have to adjust every so far.
Dogs also leave feather piles. They seem to catch and release multiple times before killing. They're more all over the place though and they go in the direction of the dogs home base.
Raccoon's - or possums have been our happy little beheaders. They don't stick around to eat the whole thing, just leave behind maimed carcasses.
When we see this, is usually means there is a tree somewhere on our fence line overhanging a fence and giving them a nice concealed entry into the pens.
Our larger predators, mountain lions and coyotes leave no trace other than a dew line in the back field, but knock on wood the yards are so human active and unpredictable, that we don't see them come within 50 yards for the most part unless they're really desperate. There are others who have chickens and other animals within a mile of us, so we don't have to be perfectly predator proof, just moreso than the other locals with animals. Mostly they'll move along to easier hunting. We have orchards around us, so small game for them is pretty secure outside of the hottest summer months when they come down looking for water. Again knock on wood.
Sorry to hear about your loss. It sucks to suddenly have to wonder where, who and when the next raid will be.