Here is Oakley, I got her as a pullet from a indoor coop and run, so most, if not all of the chickens started to peck each other, some badly on their backs right before their tail feathers. Some even drawing blood. So here's poor little Oakley, she's a couple of months younger and smaller than the rest of her new flock so they started to peck right in that spot.
I went to Farm & Fleet and they don't carry any products for pecking, so my next stop was a little further drive to a feed store. They carry one product called Rooster Booster pick-no-more cover-up lotion. It was super easy to apply directly on the affected area. It's a thick medicinal smelling liquid. The pecking stopped the next day, you could tell it taste nasty to chickens. I did have to reapply 4 weeks later and all is well in the coop. The cost is $19.50 it would be perfect to share, I can't imagine ever using the whole bottle. Roosterboosterproducts.com