That depends on how badly she is pecking at it. She may just be trying to groom.
When my rooster was attacked by a coyote, he sustained bad wounds on his back. I flushed them with hydrogen peroxide, then, patted them dry with sterile gauze. After that, I sprayed his wounds twice daily with some Vetricyn Spray.
He was very interested about what was going on there, on his back. He'd gently use his beak, as chickens do, to probe the area. But, it must have hurt at one point, because he immediately stopped. After that, he was content to let me attend to his wounds. Just two weeks later, new feathers started to emerge. I never had to cover his wound. But, then he was a rooster, and getting mounted wasn't an issue. He was also separated, from the other chickens.
Which, brings me to another thing you'll have to be vigilant for. The other hens will peck at her scabs, and may have already! So when you are ready to return her to the flock, you may want to use some Blue Kote on her back. I'd do this, even if she is wearing a saddle. If you have her outside, you'll also have make sure flies don't decide to lay eggs in her wound. Keep enough ointment or whatever medicine you decide to use on the wound.
Take care of the wound, and just observe her for a few minutes. If she pecks at it, and is drawing blood, or making her wound worse, then you will have to cover it with gauze, and vet wrap. At least till it dries out. But, if you cover it, you'll have to change the dressing twice a day, till you see it drying out and crusty. Then, you can put a hen saddle on her and monitor the wound's progress. Infection is the biggest concern right now. That won't happen, if you keep it clean, and apply some type of wound medication.
You may need more saddles for the rest of your girls, if your rooster is anything like mine!
God Bless
