Yesterday I let my 9 hens and 1 rooster out to free range and when it came time to put them away I couldn't find one of my hens. It was getting dark and I checked inside the coop and didn't see here there. I remembered that when I let them out there was one hiding around the side of the coop in the farthest corner of the run so I went around and there she was. She had a nasty bald spot on the back of her head and neck, there was a bleeding wound in the center of the bald spot and it looked like the back of her comb was damaged. dark and bloody. I scooped her up (she is very docile and calm being handled) and carried her in to the garage, where I held her under one arm while I set up a big dog crate for her. I sprayed the bald spot and the wound with antiseptic/pain killing spray and offered her food and water, which she accepted readily. Today she continues to eat and drink normaly. I treated her wound again. So, I have no clue as to how she was injured. Would a rooster do this to her? He's young and overbearing with the hens, but I don't see any other marks on her body from claws,. It's been very cold here and a few hens have dark spots on the tips of their combs that I think is probably frost bite. Would extreme cold cause a wound to her head/neck like that? I suppose it is possible that she stuck her head through some sort of opening and got caught and injured herself trying to get free, but I've had chickens in this run for 4 years and never seen anything like this. Any ideas and suggestions would be valued. Also, I am afraid to put her back in the pen with the other chickens with an open wound on her head, both because of the other chickens picking at it and also because of the severe cold. I'm considering keeping her indoors a through the weekend to keep a close eye on her but that won't give the feathers a chance to grow back. Has anyone ever put a turtle-neck on a chicken? I'm considering purchasing a pair of kids knee socks, cutting the foot off and sliding it over her head and neck to provide warmth. What do you think?