You are right, you’ll see. The hen will control that and each hen is different. I think weather conditions sometimes play a part in what the hen does.
I’ve had a couple of hens wean their chicks at 3 weeks in the heat of summer. I’ve had some hens go 9 weeks in cooler temperatures but also in the heat of summer. As you can see, some have had hens go much longer than 9 weeks. I’ve had hens stop taking care of them during the day but continue to protect them on the roost for an extra week or more. I’ve had hens take care of them during the day but leave them on their own on the roosts at night. They are just not consistent.
As CT said, the hen will take care of integration. Those chicks will be accepted as part of the flock when she weans them as long as she raises them with the flock. If you isolate them you don’t get that benefit. But she does not take care of pecking order issues. A more mature chicken outranks an immature chicken in the pecking order. Most of my pullets tend to mature enough to force their way into the pecking order and be fully accepted into the flock about the time they start to lay. I can’t say anything about when the cockerels fit in. That depends so much on the individual cockerel, your space, and your general flock dynamics.
Mama will wean them long before they are mature enough to force their way into the pecking order. Until they mature, if the chick invades the private space of a higher ranking chicken they run the risk of being pecked or somehow intimidated. It’s bad chicken etiquette for a minor to invade the personal space of its betters. Until they mature enough to force their way into the pecking order, the chicks tend to form a separate sub-flock so they can avoid getting beat up by their betters. My chicks that were weaned at three weeks did this. They made their way with the flock fine but they formed a sub-flock and avoided the adults as much as they could. It really helps if they have enough room to form that sub-flock so they can avoid the adults. Mine usually sleep in the same big coop as the adults but when I let them out in the morning the young ones are normally on the roosts avoiding the adults that are on the coop floor.
It’s fairly common when a broody hen is raising her chicks with the flock that at about two weeks a chick leaves Mama’s protection and goes to stand next to some other adult hens at the feeder, eating away with them. Sometimes this behavior is ignored, at least for a while, but usually it doesn’t take long for one of the hens to peck that chick to remind it of its bad manners. The chick then runs back to Mama as fast as its little legs can carry it, little wings flapping and peeping for all it’s worth. Mama normally ignores all this. That chick needs to learn to not aggravate its betters. But if that hen starts to follow the chick to further the lesson, Mama politely and thoroughly whips butt. No one threatens her chicks, at least until she weans them. Then they need to leave her alone too.