Among my hens are two slackers. One is a Red Plymouth cross who runs from me every night, refusing to come in the coop where she would be safe for the night. I call her Lucky. Instead, she sleeps halfway up in a holly bush. Successfully, so far. The other slacker hen (or was, until last night) a Buff Orpington, a beautiful fluffy golden gal, who spends months brooding. When I went to gather eggs last night, the Buff was on the floor of the coop below her nest box. She was dead but not a mark on her, except that the feathers around her neck were wet, strange because it wasn't raining and there is no water inside the nest area. Above, in her nest was a thick black snake, as long as I am tall, as thick in the middle as my wrist, the biggest I've ever encountered (and that's saying something). He had two large lumps midway down, more than likely the eggs the Buff was sitting on. One of those eggs will kill him, because it was the next to last one of the wooden eggs I was letting the Buff brood. By giving her a fake egg to brood, I reduced her attempts to take other hens' eggs and the breakage that resulted during quarrels.
I suspect the drama that occurred before I came on scene was this: the snake came into the coop, attempted to take one of Buff's eggs, she attacked him (and believe me, she was so protective of what she sat on that to gather eggs, I had to throw a towel over her head to reach under her) so, he took her head into his gaping maw, creating the wet and matted feathers around her neck. She died, he couldn't eat her so he pulled away from her head. She fell out of the nest box, he ate the egg another hen had laid where Buff was brooding as well as the fake egg, I dragged him out of the coop (scary moment that because he was heavy and held on), threw him out the shed door. I returned to the house with the certain knowledge that this is my last chicken flock. I find no joy in dealing with snakes. Hens yes. Snakes and other predators, no.