I was gone for a week and my six chickens were in care of a very busy husband and older son who feed watered and made sure they were all locked up in the coop at night. Something had attacked one of my chickens and left a medium size open gash that looks as if there is an infection, due to exposed meaty area that is a brownish color. The chicken is missing most of her feathers on her back side and when she opened her wings all of her feathers are missing under. However she is running around and eating and taking care of herself like usual except for lifting her foot up when in standing position on the side the gash is on. Is it to late if I swabbed the gash with hydro peroxide and put petroleum jelly on the wound do you think? Or should I let it be and hope it scabs over and does not get infected? I am not a vet so I am not sure if this is infected already or not. I am also worried that the other chickens can get a disease if she contracts a disease by being wounded.