Last night my plymouth rock hen was squatted down and dead in the open chicken cage! We thought she was fine yesterday, but don't remember specifically seeing her? There was a soft leathery broken egg shell on top of the cage where they like to sit/roost. Is that a clue? It has happened before, a while ago, with none of the hens seemingly adversely affected. I didn't check her out as good as I probably should have, before I buried her. Didn't notice any wounds. All the other hens seem to be fine. Her skin was greenish under the feathers back by her butt!! I was wondering about egg bound?? Does this happen very often?? Can you prevent it?? She was about a yr. old, and so sweet, and a good egg layer. It's so sad to have one die!!!