In the case of wild life rehabilitators, their problem when receiving a wounded animal is two-fold, because the animal is not only physically injured, it is at the same time terrified (to be handled by humans). So their secret is using homeopathic medicines, administering a first one for fear, and when the animal starts eating, they give it the main one, Arnica, which is the one for physical trauma. Seeing that you have already seen a vet, and assuming that you have already perused some of the innumerable predator attack emergency threads, this is the thing that would give her not that
little extra, but that
enormous extra. I could post twenty links, yesterday (for a different chicken) I was in a hurry (but still wanted to help) and posted a very good introduction to the homeopathic Arnica, but unfortunately it was on a survivalist site, as part of a '
bug out bag' 
so my friend duckduckgo.com the search engine played a prank on me LOL. Getting organized and finding better links, since it's smart to go through life using the best that all systems of medicine have to offer, and not assuming that what Big Pharma doesn't know or
doesn't want to know because it cannot make money out of it - is not worth knowing. Any health food store that carries homeopathics would have Arnica30 it's the most used of all or you could get an emergency delivery from amazon.
https://joettecalabrese.com/blog/emergency-remedy-series-you-know-arnica-or-do-you/
Additional links about Arnica at this page.
This guy teaches at a homeopathic college and says everything that needs to be said, but has a delivery that tends to put people to sleep. Fortunately, it's just a short video.
The one for the 'bug out bag' haha, because I mentioned it. Nobody needs a bug out bag, or that's for people who saw too many movies, but everyone should keep Arnica30 around.
https://survivalmedicine.joettecalabrese.com/homeopathic-remedies-belong-bugout-first-aid-kit/
Having a bit of trouble finding the correct amazon link, because Arnica is a bit too popular. Here it is, in case you don't have a health food store close
https://www.amazon.com/dp/B012DRM98I/?tag=backy-20
If you're giving her Arnica,
we have to discuss her medication plan, please don't launch into it by yourself.
I'll check back later for your answer.