My 8 month barred rock has a very red butt and a loss of feathers around her vent.
She is otherwise acting normal and the other chickens are healthy. They have a large coop with several roosts, they free range during the day. They are on a layer feed and I give them scratch grains by hand.
These are my first chickens so I am very new to this. Any ideas?

She is otherwise acting normal and the other chickens are healthy. They have a large coop with several roosts, they free range during the day. They are on a layer feed and I give them scratch grains by hand.
These are my first chickens so I am very new to this. Any ideas?