Wow, sorry that happened to your bird. What part of her body is that?
I had a Dominique hen get savaged similar to that and survive. Most of Deuce's wounds were on her back & her ribs seemed to have protected her internal organs.My hen also had some puncture wounds into the breast muscle, but nothing internal.
I actually found a farm livestock vet near me at the time (this was in TN several years ago), who checked her over and sold me a custom formulated salve -not a huge help now, I know- but he also pointed out not to use Neosporin type antibiotic ointment products with the "pain reliever" added since that ingredient is poisonous to chickens. The plain kind of antibiotic ointment he said was ok.
The salve he gave me had an iodine base (stained the heck out of anything it got on), so maybe someone would know of a similar farm supply available product? I was surprised that the only wound care the vet instructed me to give was to keep it clean and remove the hen from any stress - she had a private suite in my master bath for several weeks, recovered and even grew back the feathers the vet had thought would not come through the scar tissue. The key to her full recovery was avoiding stress and infection.
My Dominique recovered and returned to rule the roost again for several years. Best of luck with your injured bird.