Clean the wound with Hibaclens and water or weak betadine, and pat dry.  Neosporin or other brand of plain antibiotic ointment can be applied.  In the past, I have had chickens who have healed and regrown feathers in a month, but each case is different.  Separate her in a cage within her coop and run to stay part of the flock.  After a week or so, I would start using either BluKote, Gentian violet, or Alushield on the wound and let it scab up (which will come off eventually.) The BluKote is good to use to hide the red scalp and feathers, even when feather shafts start growing back, because they become attractive to the other chickens to pick.