That hole is not suppose to be there! Its a wound and it needs to be kept clean with a spray solution to reduce pain and infection. Also probably wouldn't hurt to get some antibiotics in her water to prevent infection. Go to your local feed store or tractor supply to get some spray and some antibiotics. I know its hard to see your chicken this way and it has happened to everyone that has had chickens. Chickens have a lot of predators and sometimes illness and diseases happen. All of us chicken lovers know what you are going through and its not easy but you just got to do your best. The best of luck to you!
