YOu could spread some antibiotic ointment (like neosporin) on her wounds, once they dry enough for it to stick. Keep her isolated until her skin grows back or the others will peck at her.....that means at least a month, from my experience with a roo pecked down to his skull. Yes, we had a...
Sounds awful. I can understand your instinct.
For what it's worth we had a young roo who was brutally pecked, and eventually made a full recovery, but it was his skull that was exposed (shoulder to comb) not his back. Not sure about ducks.
For Kip we kept him in the house with feed and water...