If you can clean the wound area and check to make sure there are no internal injuries, you can stitch the wound closed and hopefully the chicken can/will recover. If you can give the bird a couple of days of antibiotics to help prevent infection, that would probably be beneficial. Keep the bird in a calm, clean, darkened, confined area to rest and heal. Make sure it has water and food. Then just hope for the best. If you go check out the sister site: https://www.backyardchickens.com/ There are many examples of birds that have been torn apart, burned, etc. and survived/recovered. There are also lots of experts over there that will offer help. As always, pictures are worth a thousand words and make it a LOT easier to provide guidance. Best of luck with the bird.