Sorry about your chicken. That is a very serious wound, and infection is a big threat. Is there any way you could take him to a vet for care? He has a good chance of survival if his wing is amputated, and as long as he doesn’t have internal injuries.
What do you have for disinfecting a wound? Betadine, chlorhexidene or Hibiclens, or Vetericyn are very good to use to initially clean the wound. After cleaning (pat the area with the disinfectant,) I would cover the area with a moist rag covered in betadine or saline. That would be just to keep the tissue moist. Antibiotic ointment (Neosporin, Triple Antibiotic, or Polysporin) are all good to use on the wound after cleaning twice a day. Keep him from flies perhaps inside in a crate.
He may need to have his wing amputated, and they can survive with only one. Antibiotics might be necessary. Feed stores do not have many for wounds except procaine penicliin G which is given by injection. Do you have any or can you get anything from yoru vet?