You are welcome:-) You don't have to go to a vet for antibiotics, most vets won't even treat chickens. Go to your farm store, get LA200 and some syringes with small needles. I am sure if you do some looking on here, you will find dosages in past posts. You inject the antibiotic into the breast...
Don't pour any more hydrogen peroxide on the wound. Full strength is too strong and will stop the tissue from healing. I would recommend antibiotic ointment and wrap it loosely with gauze. Vitamins and electrolytes are good. She may need antibiotics as well. Add a little sugar or molasses to her...