I'm fairly new to chickens, but I recently found one of my two month olds missing the flesh on the near half of her wing, with the end half bare bone. This is day 12 of her recovery, and I had the same concerns, especially since there was literally only muscle and bone with very little skin. I was advised on here to clean daily with a half betadine/half water mixture, then coat with neosporin or antibiotic ointment, then pour sugar over the ointment, and gauze up. I did that for my pullet till day 9, which scabbed over completely, looked real black and crusty. Day ten the scabs were lifted, and the all the black crusties basically fell off, undernearth was pink new skin. I've been using medical wound honey the last two days, and the results are amazing. I can't see any bone anymore, day 12, I'm hoping for a full recovery by day 30, if not sooner. I hope this helps, speedy recovery to you both!