Aggression within my flock - what could be the cause?

[nathanlevi]

I have four Barred Rock hens, all sisters just over a year old. They paired-off by size soon after I brought them home. The problem I am having is one of the smaller hens (June) who is the broodiest of the four is getting chased and attached by her two larger sisters (Patsy and Tammy). I stopped Patsy yesterday when she had June to the ground, pecking at her mercilessly. I also opened the coop door to intercede when June and Tammy were on the roosting bar, with Tammy appearing to get under June to push her off the bar and Patsy below, jumping and pecking at June -- this tag team aggression blew my mind.

I have seen June's buddy, Loretta, move in front of Patsy and Tammy to stop them from chasing and pecking June. Loretta never becomes the object of aggression when getting June's back.

June's vocalizing has been primarily 'agitated and aggressive' since her recent two-week period of brooding. Her vocalizing is very much what she would make when I'd put my hand under her to pull eggs - and - June would make the same sounds if any of her sisters would come near her while she was on her egg (and or her sister's eggs).

It has been six days since June stopped brooding and the aggression towards her began. I've watched the structure of, and the fluidity of how my flock's pecking order works. This is very, very different. So far, June has only lost a few heathers, but I worry about her physical and mental health. I would love to hear anyone's experiences or theories.

 

[sourland]

To a degree they are regarding her as a 'stranger' because of her changed (broody) behavior. As long as blood is not being drawn things should resolve, and the more normally she acts the sooner peace will be restored.

 

[nathanlevi]

I have assumed the aggressive behavior was related to the change in June's behavior. I'll continue to keep my eyes on them all. Thank you.