I have a hen I believe is ill. Her tail feathers look awful and it looks like something has been eating on them. I have not observed any feather eating or picking by her or the other birds when I am around them. Yesterday evening I noticed her comb was much darker then normal but not blue and her skin around her eyes looks pale. Her eyes are not vibrant and she is puffed up like she is cold when it is in the mid 40's and 50's during the day. She is the last to come out of the coop and the first to go in for the night, sometimes she stays in during the day. She tends to hang out on her own for the most part, but today we let the chickens into the garden area and she joined them but stayed to herself. All the chickens have access to 20% layer feed & oyster shell all day long in addition to them free ranging all day as well. I keep their water fresh daily and try to keep their coop clean as possible with weather permiting. January was unusually cold, I suspected a few of my other hens not feeling well during our cold spell but they seemed to have snapped out of it and look healthy. I weighed her, she is around 4 lbs 8 ounces. I can't tell what her stools look like but from where she sits on the roost at night she has been runny. She also has some urates on her rear that is a little sticky runny yellowish looking. She doesn't seem to have a breathing problem, and no discharge from the nasal area or eyes. I checked her over for lice and mites and couldn't find signs of anything. Her feathers have looked bad since about December but several of our chickens were going through a molt and figured she was going through one as well. I really don't know what to do for her so if anyone has any opinions or recommendations I would love to hear them. If it helps at all, she is a SLW. I am starting to think her body is not absorbing her food properly to give her the nutrition she needs. I don't know if antibiotics like Duramycin would do her any good. I don't know if she is laying either. I feel I need to give her a chance but don't know what to do. I can separate her if needed in a temp pen inside the coop so I could give her antibiotics and not have to treat the others and save their eggs. Sorry for the long post, but I really don't want to lose her!