Help please. We recently added 4 young silkies to our flock of 10 hens and 1 non aggressive rooster. Our birds are enclosed in appropriate fencing buried in the ground and doubled 18 inches up, about 8 feet tall and enclosed on the top. One by one something attacked our silkies and we found them beheaded and entrails exposed or missing. We can find no way predators can get in. Does anyone have any idea how this might be happening? Any similar experience or any advice. Thank you.