I went out to my coop this morning and found one of my hens were just laying on her back dead and I'm worried for my other girls! She was acting normally yesterday, they all had plenty of food water and shade. When I found her she was on her back and her wattles and most of her comb were shrivelled and black, and some liquid came out of her mouth when she was picked up. All my other hens are fine, they aren't lethargic and are eating and drinking. Can anyone help me find out what killed my hen? I need to keep the others safe.