How long to keep them separated?

They need to be somewhat close in size. I start integrating my flock in the 8 week range. I start with a fence between them so they can see each other and b/c they free range it works well this early.

 

I keep my newly hatched chicks and broody separated for about two to three days. Not weeks, days. This is just long enough for them to learn to eat and drink without competition from the other adult hens. Then I turn them loose to roam with the flock.

The chicks don't have to be big enough to defend themselves. That is Mama's job. By the time they are weaned, she will see that they are fully integrated with the flock. If you keep them separated until the chicks are grown, the hens will have to be reintegrated with the flock and the chicks will have to be integrated. There are risks in how I do it, but I personally think there are more risks in integrating later.

I may have different circumstances than you. When I let them roam with the flock, they really roam. They have no fences restricting them. If you are tight for space, then I think you are at greater risk. Of course you will be at greater risk when you integrate them later if you are tight for space.

Just because they are integrated does not mean there is no danger. Integrated just means that the other chickens accept them as members of the flock and should not go out of their way to attack them as intruders. They are still at the bottom of the pecking order. Occasionally you will have a chicken, usually a hen, that will go out of her way to attack chickens lower in the pecking order. She's not doing this because they are chicks. She is a brute. She will do the same to older chickens establishing themselves in the pecking order. Most flocks do not have these "seek-and-destroy" chickens, but a few do. Each chicken has its own personality and each flock has its own dynamics, similar to any small group of humans. I can't tell you exactly how your chickens will behave. I've had roosters go out of their way to protect chicks when they get separated from Mama, but my current rooster does not do that. They each have their own personality.

The risks from them being lower in the pecking order is that if they invade the personal space of a chicken higher in the pecking order, that chicken may peck them. They don't always, but sometimes they do. This is not an attempt to kill the lower ranked chicken, just to discipline them and teach them proper chicken etiquette. Of course there is some danger in a big chicken pecking a chick, but I've never lost a chick to that. Others have, so it does happen. What will normally happen is that the chick runs as fast as it can back to Mama if it is not yet weaned, or if it is weaned and on its own, it will just run away. The lesson has been taught and life within the flock is tranquil again. My broodies usually ignore that pecking order stuff as long as the chick quickly runs away. But if the hen keeps attacking the chick, Mama goes into protective mode. The danger is that the chick cannot get away. If it is trapped against a fence or in a corner, the older chicken may take that as a challenge and keep attacking. That is where space comes in.

There is another risk. If the chick gets separated from Mama and is trapped with older chickens, they may kill it. They are just feathered velociraptors, carnivores, and can be cannibalistic. I've had that happen once. If Mama can get to the chick and protect it, that usually won't happen, but Mama was on the wrong side of the fence and did not understand she needed to go to the gate to get in with her chick.

I'm probably making it sound as if it is more risky than it really is for me, but I'm trying to tell you some of the things to watch for. In my circumstances I think the risks are much less for Mama to raise them with the flock.

If you do keep them isolated, be very sure the chicks cannot get out of the confined space. If they do and Mama cannot get out to protect them, they are at risk from the other chickens. There are risks any way you do it. Just try to pick the one that is best for you.

Good luck!