Easter Eggers attacking others, pulling neck feathers

[AtlantaViking]

I have noticed a couple of my Easter Eggers attacking other hens by pulling neck feathers. Plenty of room to roam, plenty of food, just random attacks

 

[Plchickens]

I have had the same problem with two of my Easter eggers also. But mine are attacking one of my Pekin ducks to the point they have injured her eye. I had to move her out of the pen to protect her. Not sure why they have started doing this now since they have been together from day one.

 

[rosemarythyme]

Any photos of the damage, and of your coop and run? Also what are you feeding them, specifically protein % of feed and treats, if any?