Pain is different in prey animals compared to predator animals like us. They don't react to pain or consider pain the same way we do. They have different brain wiring. For us, making a fuss over a small pain is perhaps helpful, but it is not the case for a prey animal, as showing, or BEING, in pain will get you singled out. I'm sure they know and feel pain, but it is different to us. I wouldn't think that pills are very meaningful. Gaping wounds do not stop chickens going about their daily lives. It's weird and different to us. Fixing the cause would help more than treating the symptoms.
Looking at the depth of that wound I would be pressured to think that amputating the wing would be best, WHILE doing the amputation, you'd want to leave enough skin and leave it in a shape that is going to be easy to seal up or at least hold together. perhaps the same kinds of tapes that are used in hospitals. Try putting a piece of tape on either side of the wound that you make and then using smaller pieces to bridge the gap. It would make it easier than a single piece which will pull the wound to pieces if removed or refreshed, but two pieces one on each side may suffer less problems in this regard.
As a rule, things heal best by drying out first, that's wounds in flesh I would think, rather than down to the exposed bone like this one, closing something over the bone so that the flesh can heal would be important because it's hard to make new flesh and cover over the bone.
You'll need to bind her down so she doesn't move about while you work, using cloth, rags, and so on, keeping her from watching you. You may save her life, but she may not forgive you without a lot of work, if she forgives at all, but that may not be important.
Luckily people have generally studied chicken anatomy in some depth at the university of dinnertime.
It is hard to know if you can save her, because her system is open to everything and it can and has already got in. She seems to need something in the way of amputation, otherwise you'd be looking at making her comfortable in a cloth, sitting in the bottom of a hole in the garden, where she'll be ok with you eventually covering her over with the cloth so you can bring down a large stone as fast as you can, removing her ability to feel pain and sending her on her way. I do hope you'll be ok, and I do hope her spirit will be ok whatever happens.
The best way to stop the killing by ground predators is to be pro-active with TRAPS, I've built one with a $10 electric eye infrared beam as the trigger and a secondhand car central locking actuator to drop the door, the $12 solar regulator that does the solar thing with the 12v battery also puts out voltage only during darkness when chooks are asleep. It prevents cats and foxes taking such a toll on the chickens and chicks as once they did, I do not know what would help with AERIAL PREDATORS except making certain they have places to hide where they can only go on foot, bushes usually do this, perhaps your place is missing bushes in the coop. If the coop is that small, it should be easy to net.
Wow! She is a lucky girl,both to have survived the hawk and to have you taking care of her! I would be doing all the things you are. Keep cleaning and wrapping it up until closed. It's going to take a while.
Just keep doing what you're doing. It will take a while for new tissue to fill in the area, but it will in time. I'd trim all of the feathers off that wing to ease her efforts by removing as much weight as possible from it, that might help a bandage stay on better too. Are you using sports tape/wrap that stuff that stretches & sticks to itself? I don't know if you can get any Granulex spray, spray a bit in medicine cup and mix with a bit of triple antibiotic ointment has helped many wounds heal in my nursing career.
