Hello and welcome to BYC!
Many times feather picking and eating starts from boredom and being cramped. Once they start this bad habit it's difficult to get them to stop. So I'd try and give them more room and keep them busy either free ranging or things in their run to entertain them. If enough time passes, they forget.

Many times feather picking and eating starts from boredom and being cramped. Once they start this bad habit it's difficult to get them to stop. So I'd try and give them more room and keep them busy either free ranging or things in their run to entertain them. If enough time passes, they forget.