I would not cover it at all. Make sure she has shady areas that she can be. I had a hen scalped, her skull was visible. Picture below at around 6 weeks, feathers just starting to come in. When it scabs over the scab may be very thick, it will come off on it's own when it's ready. Your bird is missing a larger area, so I would expect it may take a bit longer. I kept it clean and reapplied an antibiotic ointment several times a day as needed, never bandaged it at all. Once it's scabbed enough for flies to not be an issue, you can put her in a crate in the run with the others, so they can see each other. She'll be happier and it will make reintegration easier.
