Pecking order problems?

That's pretty normal. IMHO they have to work that out on their own. She will get to a point and stop pecking so much. The older the new ones get, it will ease up.

 

It’s not so much the size of the leghorns as their maturity. Until they mature enough to make their own way into the pecking order they will rank below the others. That’s often shortly after they start to lay, but not always. Their final place in the pecking order won’t be determined by size, but by their spirit.

Your space is probably a good part of your problem. One way chickens have learned to live together is in case of conflict, the weaker runs away from the stronger or just avoids them to start with. If they don’t have the room to run away the one doing the attacking doesn’t realize they’ve won and keeps attacking. It can get real bad.

You’re certainly on the right track by making the run larger. It doesn’t matter if the space is in the coop or coop and run, it just needs to be available when they need it. I don’t know how you are adding to the run, but if you can manage to keep the existing one intact so you can isolate a chicken in there or open a gate and allow them all to have access, that could give you some flexibility in how you manage them.

I’m not exactly sure what is going on with your red hen. It’s possible she could be a real bully and a brute and just totally enjoy beating up those new pullets, but probably not.

Chickens can be territorial. They can recognize chickens that belong to the flock and may attack any strangers. This does not happen all the time but it happens often enough to be a concern. If you can house the pullets across wire from the others for a while, or keep the red where she can see them, she may come to accept them as having a right to exist.

Or if you keep the red separated for a while and the others get along fine, when the red goes back in she might have lost her place as dominant hen in the pecking order. She may be too busy reestablishing her place in the pecking order to bother with the pullets. It’s even possible she may never regain her top position.

It’s interesting when you say she jumps on their back. The mating ritual is not just about sex, it’s also about dominance. The one on bottom is accepting the dominance of the one on top, either willingly or by force. I’ve seen a dominant hen in a flock without a dominant rooster go through the mating ritual all the way to touching vents to show her dominance. I don’t know if the hen jumping on the other’s back is an attempt to kill her or an attempt to force her dominance on her.

Hopefully you can get something useful out of this. Good luck!

 

Perhaps you can separate your red hen for some days and then reintroduce her. Many people have commented on that helping a dominant chicken issue. Good luck!