Broken Feathers on EE?

[Pentatonchix]

Hello All,

Around a week ago, I saw that some of my EE's back neck feathers were broken. The other hens peck at her muffs, but I don't know how they could get to these feathers, as they are hidden by other feathers.

Here are some pictures:

Thank you!
P

 

[sourland]

Looks like feather pecking/plucking to me. It starts out as grooming and sometimes escalates. Birds just stand there and let it happen.

 

[Pentatonchix]

Looks like feather pecking/plucking to me. It starts out as grooming and sometimes escalates. Birds just stand there and let it happen.

Thank you. What should I do to prevent this?