I have four young chickens now, they were all born mid to late March, so they are about the same age, give or take a week. I started with three mystery gender and breed chicks that my brother-in-law found in the street (cue to long story involving a neighbor who lets hi chickens free in the street, and us finding dead chicks often, thus we kept these ones we found alive and separated from their flock). Two of the pullets seem to be of a regular size, but one is very small, so I think she is a bantam mix. My brother-in-law wanted to get a rooster for the hens to both help protect them from stray cats and because for him it just feels more natural to have a rooster with hens. Well, I got a rooster, a regular light brahma from a lady I know who raises chickens every year, and she got some cockerels she had to rehome. Now, at the beginning everything was fine, but my bantam mix, Rusty, got sick with a yeast infection after I treated her for a sour crop. She's had to spend pretty much every night for the last 2-3 weeks inside the house, because Roostroyer (the brahma) began to peck her. He's sweet with the other two pullets, and they even flare and peck at him to put him in place, so he never bothers them. He, however, pecks at Rusty mainly in the back when she gets close to eat, and since I started to let her get in the coop to sleep now that she's better, he pecks at her rather hard when everybody is settling to sleep. Tonight I was watching them interact and he even made her run out of the coop into the run with his pecking (they are free range most of the day, my coop has a run but it's rather small, so I only lock them inside at night). He even got out of the coop and into the run to chase her, but I grabbed him and didn't let him go until Rusty got back into the coop and settled down. Then I let him back, to which he got into the coop, went to peck at her again a couple of times, and finally everybody settled down. I know I've made some mistakes about adopting the brahma. I didn't know how big my hens would be, I didn't even know I had a bantam mix until I saw she is still smaller than the other two, and I had never seen a brahma chicken in person, I just read about them when I knew I had the chance to adopt a cockerel, and I know the breed is very tame and gentle. I am concerned about how he treats Rusty, and because I've never had chickens before, I don't know chicken language and behavior yet . I already know I'm gonna have to upgrade my coop/run to accomodate him, but I'm worried about him pecking her and bullying her at dusk and when they all gather to eat. My nieces and I handle the chickens all the time so they never attack us, and I make sure Roostroyer knows who the boss is. I just don't know how they interact with each other and I'll have to choose between Rusty or Roostroyer if things don't get better. Edit: also, my two pullets and cockerel are about 12 weeks old, Rusty is 11 weeks or so, she's a few days younger. The older chickens already cluck, Rusty peeps, and peeps peep peeps a lot. When are chicken supposed to break their voices?