How do we stop feather plucking to point of bleeding?

[ThimbleMicroFarm]

Hey BYC community,
We have 8 month old hens (first time chicken keepers). A couple of the girls are plucking/pecking feathers near the other girls vents and tail feathers to the point where we have made visits to the vet because of the bleeding. We don’t know how to stop this, have bought numerous treat toys to prevent boredom. They have plenty of space (6 chickens with two full runs and a large coop).

Is this a bully issue? If so, how do we go about correcting? Any other suggestions? We’ve read as much as we can on the issue. Thank you!

 

[rosemarythyme]

How "large" is your space, both coop and run? Your definition of large and someone else's may not match up, so actual measurements help.

What's in the space? Is it just a big rectangle or is there stuff for them to interact with?

Photos of coop and run can help.

Also what are you feeding them? A photo of the nutrition panel or a link to the product would be great.

What breeds are the birds?