We have had chickens attacked by raccoons and tore open pretty good. We took them to an older fashioned vet which is before we found our avian vet ... But the farm vet cleaned the edges, sutured, and cleaned everything and then had us fill the other holes with Neosporin ( not the off brand or the one with pain meds) then at home she had us soak gauze in a solution of 9 parts water to 1 part bleach, ring it out, and put the gauze on the wound and wrap her up so that the gauze would stay on. Keep the gauze wet all the time and no flies will come around.... Change every 6 to 8 hours ... Don't make it any stronger cause it will burn the skin... This kept it from getting dirty and from flies laying larva till the edges were healed enough . It might sound strange but worked really well and never had a problem with flies during healing. She also made her a little shirt to slip over and hold the gauze on and the staples... Cause our chickens like to pull out the staples... But also make sure it's cleaned out good first!
This link is about that vet trip and some of her wounds... Hope it helps.., good luck... And well wishes for your girl. Ignore all the typos in my old blog pls lol
http://respectlifeeatveggies.blogspot.com/2010/08/big-reds-trip-to-vet.html