This morning my husband went out to get our chickens ready for the day, we keep them in an enclosed coop closed up at night and )their run is attached to the coop, No predators can get in so we don't know what happened. We do have a rooster, he is a Delaware X Hampshire Cross (Indian River). Anyway, when my husband went in the coop she was laying across the pan we have their oyster shells in, and he said her feathers were all ruffled a lot at her neck where the rooster pecks them . He seems to think the Rooster was trying to peck her while she was eating the oyster shell and it either broke her neck or choked her and she died, I am just heart broken poor little thing was only 5 months old and we have them tamed, except for rudy, he is flighty. Any suggestions as to what happened would be greatly appreciated. She was not sick or sickly in any way. so an illness is not a factor.