I know the title is vague. I have a RIR hen who isn't acting quite right. I have a heat lamp over my waterer, and she tends to stay under the heat lamp. She stays all puffed up, so she looks kind of rounded. She is light as a feather when you pick her up, although she seems to eat fine. Her comb has some black in it, like perhaps she has gotten frostbite, but that isn't really possible. They haven't been let out this winter except for a day or two when it was in the 40s. When she leaves the heat lamp, she will sometimes go to the door way or into a corner to protect herself, although the other hens don't seem to pick on her to any great extent. I have isolated her from the other hens, with food, water, and another heat lamp. I haven't given her a thorough examination, but she doesn't seem to be crop bound. Anything else I should be doing for her?