One of my Cuckoo Marans suddenly lost a lot of chest feathers over about two days and I'm not sure why. My other chickens are also missing feathers but not as much and not as fast. The feathers are mostly missing around their butts and at the base of their tails. I am pretty sure I have a plucker, but what else could cause it? When I clean every week I use DE, we let them out a couple times a week to free range, they also get table scraps. Also, what helps them to re-grow their feathers? Some have had the same bald spots for a couple of months now.