I have 3 mutt pullets that are about 12-13 weeks old. One of them is small so I'm guessing she is a bantam mix. I adopted a regular brahma cockerel some weeks ago ago, same age, and after keeping him isolated for a couple of weeks as an extra precaution (I know he was healthy beforehand since I know the lady who raised him), and after a week or so of introducing them through a chicken run I let them hang out together. They do mostly well together, but ever since I had to keep my bantam Rusty inside the house to treat her for a yeast infection for some days, he began to peck her when I brought her out again. It's been two weeks and while he doesn't hurt her (no wounds, no loss of feathers), he still scares her away from the food and also wen they are getting inside their coop to sleep, as soon as he sees her, he walks to her and pecks her, making her run out of the coop and into the run. I don't worry too much since she's not getting hurt, but I'd like to make him stop that behavior. What I've been doing and that seems to be working is that as the pullets go inside, I grab him, pet him firmly in front of the girls, make sure I gently push his head down so he looks submissive to me, and after 5-10 minutes I let him go in the run, and he slowly walks into the coop. When I started doing that, he would just go in and settle, and only two time he pecked at my bantam, to which I grabbed him and did the petting thing again. I don't see the pullet get so nervous in the coop anymore, at least not as much as before, so I guess it's working. Now my question is: why does he do that? The bantam never challenges him, she always runs away from him when he goes into fluff chest bumping mode. the other two pullets do it and he leaves them alone, but he is still "bullying" the small one here and there. I thought after two weeks he'd finally get used to her, but he still does that. He hasn't draw blood or ripped feathers, so am I worrying too much? I've never had chickens before so I'm not too sure if this is normal behavior and rusty is in not real danger. Edit: he is a very good rooster, all the chickens are very docile and friendly. I got him because my brother-in-law wanted one, and I thought it'd be a good idea to have him as extra protection for cats that sometimes wander in the backyard. I had never seen a brahma before, so when I saw how big a fluffy he was, I was a bit concerned. It turns out that my two bigger pullets kicked his butt right away and put him in his place, just Rusty the bantam runs away from him. He is a giant compared to her, and I didn't realized Rusty was a bantam mix (she's about a week younger than the other two pullets), after I saw that all the girls got their feathers, but she just doesn't grow as much as the others. Also, mandatory picture of the peeps.