Hi we have snow now and its really cold. We habe three hens all different breeds. The Sussex Line chicken is the only one not laying and in the cold its behaviour has changed the most. It sits with its neck in feathets plumped out as if its trying to keep warm and seems sleepy. Also its wattle and crown seem to have reduced to nothing in size. The other two chickens are behaving as if they are in normal mild weather. Is this normal? She is certainly eating.