Jess, just checking in to let you know I am thinking a lot about you and your poor little girl, and hoping she improves. I know how awful it must be to not know what will come of it.
A completely different situation but in the mid 90s I had 2 roos show up out of nowhere - they were the best of friends - beautiful to watch really. I had no chicken accommodations back then so was searching for homes for them, though I set up my garage to be their nighttime camp. Then we had a sudden horrifically bad snow/ice storm and something snapped in them and they had a terrible fight. There was blood everywhere. I found one of them stuck to the ice, barely alive it seemed. I brought him in the house, kept him in a quiet comfy place with very soft low volume classical music playing just for him. Everywhere I called for advice said to eat him, that he was toast anyway. I did not! That poor fellow did not move, eat or drink for 7 days (if I knew what I know now I would have gotten fluids into him somehow). On day 7 he stood. Long story short, he got better every day after that and made a full recovery. I still remember the first time he crowed after that, marking his true return to the land of the living. Not the same situation as your girl, because I don't think he sustained a head injury, and I think yours likely did. I only mention it because sometimes these beings pull off amazing recoveries.
I just hope she is not in awful pain. I am wondering if at least some pain relief may be in order here in the form of the aspirin diluted in water. It is also an antiinflammatory and since she's got some swelling..... If internal bleeding, it would be a bad thing. If not, maybe it would help her. Anybody want to comment on this?
JJ