It is cold where I am and I noticed one of my chickens was laying by the heat lamp. At first I thought nothing of it but today she seems very lethargic and is laying with her head in the corner and her eyes closed. Her breathing is deep and labored and she refused food and water. Both chickens stopped laying before winter so I don't think it's a stuck egg. Neither of them have left the coop for more than just water most of winter but the sick one hasn't been out in even longer. She is also losing feathers on top of her tail and her comb is bent over. Her vent isn't clean but it's not horrible, she's white colored so it's been that way her whole life. Any suggestions???