The OP has not been on since 2021.Did the chicken survive?
We are dog sitting and after several days of not messing with my chickens they got one. We found her and she has some damage to the top of her wing and her chest, her crop seems to be exposed.
She is very very alert after not finding her for about 24 hrs. I gave her some electrolyte water, feed and sprayed her with wound care.
If you wish, start a thread about your hen. Post photos of the wounds.
Here's some good instructions for treating an injured bird:
https://www.backyardchickens.com/threads/wing-ripped-off-by-predator.1614503/post-27574058