Hi
I'm sorry your hen is sick.
Feather loss and bleeding from the head is almost always caused by other chickens, either pecking order issues, mating damage or the chicken is sick and the flock have set upon her. It sounds to me like the latter and your girl is sick.
Was she definitely broody 2 weeks ago or just staying in the nest box overnight. What other signs of broodiness did you see? If she is emaciated, she has been losing condition for some time and I would suspect that she was ill 2 weeks ago. What did you do about her "broodiness"?
How old is she? Has she shown any signs of lameness or wry neck or a dropped wing in the past few months?
Wasting/loss of body condition is often associated with crop impaction. Have you checked her crop function? Is it going down overnight? Check at bedtime and remove access to food and then check again first thing in the morning.... when it should be empty. If it is not, then you need to start massaging it to try to break the contents down. Coconut oil is beneficial in helping with this process.
You are right to provide heat for her if she is skinny. A heat source is one of the most beneficial things for a sick bird.
Personally I am not a fan of using antibiotics unless there is a known bacterial infection. They damage the gut flora which is not helpful in an already sick bird and overuse has lead to an increase in antibiotic resistance, but I appreciate that everyone has their own ideas.
If you are concerned about possible internal parasites, get a faecal sample examined for worm eggs. This can be done by any veterinary practice or there are mail order lab service options. Again, putting unnecessary chemicals into her body when she is already sick is not beneficial, so it is important to assess whether a wormer is required and if so, which one.
Talking of faecal samples, what does her poop look like? Can you post a photo of her poop and the hen herself?
It is good that she is eating and drinking. Do you have some Poultry Nutri Drench or Poultry Cell. These vitamin rich tonics can give them a boost and help support their immune system. I would also give her some quality treats like meat, egg, fish, insects. Liver is relatively cheap and full of good nutrients..... only feed these if her crop is functioning properly though and make sure she has access to grit in her infirmary cage.
Other common things that can cause emaciation are being bullied from the food station, cancer and in extreme cases, parasitic burden.
Good luck with her.
