Feather plucking/ loss on backs & tails?

[KCchickie]

My 4 month old pullets (18 of them) have been plucking each other's backs &

tails. First, I think they might have been overcrowded in their brooder which started the behavior. So we released them out at 8 weeks and now they are in a very large indoor (12' x 12' stall with roosts, hiding spots, nest boxes) and outdoor (20' x 40' electric paddock), with access to fresh grass all day. Chicken heaven really! But they seem to continue the plucking at night? Also, only my cochins, silkies, and polish cresteds are doing it. The others are unaffected. What can we do to stop this? We tried covering their backs with rooster booster a few times, but it didn't do much. Any advice you have is welcome!

 

[Poultrybonkers]

plucking feathers is from lack of protein but at this point it might be a learned behavior and may not stop I would try upping the protein of their feed to at least 22% if in a few weeks it don't stop then they never will

 

[Perris]

anti-pecking spray such as scarper (tastes bad, no other effects) works to help break the habit now it's formed.

 

[PirateGirl]

it looks a lot like rooster damage... how many males vs. females do you have?

 

[KCchickie]

Only 4 months old, we don't have a rooster yet