You've received lots of good advice for taking care of the wound, I just wanted to share this link, with pictures of a fairly serious wound throughout the healing process, which may help you as you go along to kind of know what it's going to look like. Yours looks deeper, with some muscle damage, but I don't think it's hopeless. If she takes a turn for the worse you can always deal with that then. Best of luck! They often recover from some pretty awful wounds as long as you can keep infection at bay. http://richie-cunningham.com/2012/04/11/chicken-wound-healing-process/