At
Walmart, CVS, etc., you can buy Hibiclens (Chlorhexidine) or Povidone Iodine. I would use one of those to flush and clean the wound out really well.
Trim the feathers from around the wound so you can see it better and so they aren't sticking into the wound. Get more photos after clean up and trimming.
A very good cleaning out of the wound may take care of the odor and infection, but sometimes an oral antibiotic may be needed. Amoxicillin can be ordered online as can other antibiotics. If you have a local Mom/Pop feed store, you may luck up and find Amoxicillin, but usually it would need to be ordered.
IF badly infected, you can use Penicillin G which can still be found in most feed stores like
TSC. You'll need some syringes and a pack of 20gauge needles as well. Dose is 1/4ml injected into the breast muscle 1/4" deep given once daily for 3-5 days alternating sides.
Once you clean that wound really well, then apply a thin layer of triple antibiotic ointment.
Since the wound smells, clean/swab daily with the Chlorhexidine (preferred) or the Povidone Iodine until you can get meds started.
Work on hydration, give her a bit of sugar water or electrolytes for the first day or so. Once drinking, then offer some wet feed.