Hen mounting another hen, then all the others attack!

[carolinatomato]

I went out to the coop run one day to find 4 chickens (2 black sex links & 2 RIRs picking on one (RIR), to the extent her comb was bloodied and around her eyes too. She was just cowering in a corner with her head down. I pulled her out and put her in a separate coop and run till she recovered. I thought she was sick, but she is fine and laying. These 5 chickens are just over 2 years old and have been raised together.

I’ve been letting her out in the yard some, and gradually letting one or two of the others out to see if they would get along. Well today, I saw her twice try to mount one of the other hens and after the 2nd time, all hens converged on her and were pecking at her head. I separated her again.
I read hens mounting hens was normal but not all the others ganging up on the one that’s doing it.
Does anyone have any thoughts or suggestions? Thanks, Donna

 

[Judy]

The one doing the mounting is trying to establish that she is dominant. For some reason, the pecking order conversation has escalated in your flock to the level of drawing blood. One way to shake this up is to remove the dominant hen (who may or may not be the one doing the mounting) for a week or so, out of sight of the flock. When she is returned, she should be a stranger to them, at the lower end of the pecking order. You might also be able to shake things up if you can move them all to another area or let them loose in a much larger area during the day.