@AnyaTotoro
We had a hen who lost most of the skin on her right thigh, as well as gashes in her rear area. She was so badly mauled at first I thought she was dead. When I realized she was in shock and alive, I almost put her down, due to the amount of damage. We decided to try to save her first. All of the wounded areas were cleaned, we placed her in a large plastic bin in the den with a towel on the bottom and a towel on the top of the bin.
She was given pediolyte (unflavored) and after 2 days of not eating we began giving her a layer pellet omelet every day with free choice layer pellets. We also keep her wounds covered in Neosporen at all times ( no pain relief, plain name brand Neosporen). I chose the name brand because the hen's body heat causes it to melt into all the gashes and such.
DH and I are both RNs and treated her like she was in ICU. We never let anything dry, kept all wounds covered in Neosporen at all Times. We interacted with her on a regular basis, often just re moving the top towel so she could see what we were doing and talking to her. Some times I would just sit and pet the back of her head and neck and she would purr.
It took months for all the skin to grow back and feathers to start growing in. Last week she went into a see no touch cage outside and today she reintegrated with the flock with us overseeing the procedure. Very little pecking, over all things went better than we thought they would. She is currently roosting with her flock mates, soundly asleep.
It is a long road, but I would keep giving her pediolyte, egg, and attention. Keep her clean, (change the bottom towel often) and all wounds moist with the Neosporin. She should heal just fine, Good Luck to you and your hen and please do not hesitate to ask if there are any questions I can answer, as I have just finished what you are just starting.
Our hen ate some of the Neosoprin when we put it on her, it did not hurt her at all to eat some.
Please let us know how things are going!