Backyard Fowl Keepers

I had a similar experience with one of my chickens who was picked on. What helped in my case was using a slow integration technique with a little bit of distraction. I provided a new perch or something different in the run that distracted the flock, so they weren't so focused on pecking the Leghorn. Giving them new things to explore can be helpful in diffusing aggression.

You're doing the right thing by gradually reintroducing her. The other chickens might just be asserting themselves, but keep a close watch for any signs of aggression, like pecking or more aggressive chasing. If the behavior escalates, you may need to separate them for a little longer and try again. If they don't settle down, adding a couple of new birds to the flock might help break up the aggression.

I think the way you're handling this is good so far. Slowly reintegrating the Leghorn while giving her time to adjust is key. Chickens sometimes need time to rebuild their confidence in the flock after bullying. You could also try adding a few distractions in the coop, like new perches or toys, to help take the focus off of her and spread the chickens' attention.

Your approach seems pretty solid, but one thing that can sometimes help is putting the Leghorn and one of the more docile chickens in a small area together while the other flock members roam outside the coop for a while. This gives her the chance to reintroduce herself with less pressure, while still being able to interact with one other chicken.

It sounds like you're doing a good job trying to ease her back in gradually. The issue could be that the flock has developed a pecking order, and the Red might be asserting dominance. I recommend continuing the gradual reintegration, but also consider using a “buddy system” where the Leghorn is in the coop with one or two calm chickens during the day. That could reduce stress and help her adjust. I'd also recommend observing them closely when she's in the coop, just to make sure there's no excessive bullying.

I would recommend continuing to let her spend time with the others during the day, but try to monitor them closely. Sometimes chickens need to reestablish the pecking order, and it may take time. If you're still concerned, you could try separating the aggressive bird for a day to reduce the bullying, then reintroduce her to the flock. This might reset the dynamics and help the Leghorn adjust better.