Are you sure that was coons? That behaviour sounds exactly like what weasels did to my neighbour's flock. I had a coon problem my first chicken winter, but they would grab one, eat it, drop the carcass and leave, saving the rest of the birds for another night. Third time my husband busted them red-handed; he chased them out with a hockey stick, giving one of them a good smack on the butt, and they haven't been back since! Even with the awful winter we're having this year I was totally expecting them to return, but nope!