One of the grey squirrels that frequents our bird feeders has a open wound on his neck. Looks like maybe he escaped the wrath of a hawk. He is otherwise behaving normally, but the wound looks raw and painful. Just wanted to know if there is something we can do to help him heal faster. Wish I could put some antibiotic ointment on it, but that's probably not realistic. Is there a food we can offer to help his immune system?