Integrating 12 weeks old flock with older flock and a rooster

[aldarita]

I have 4 nine week old welsumer chicks (unfortunately one of them turned out to be a cockerel) and 2 barred rock pullets. They are in a pen that has a fence separating the adult flock yard. They have been seeing each other for 5 weeks already. I plan to integrate them when they are 12 weeks old but my concern is that there is a rooster in the adult flock (he has 14 hens in his harem) that might want to mate the 12 week old pullets whom will be already stressed because of the integration. The cockerel is young and might be able to get along with the rooster (hopefully) if not, he will have to be rehomed.
I appreciate any comments anybody has about this concern of mine, maybe I should wait until they are older to integrate them but everything would be better if I integrate them sooner since they will have a bigger yard to roam and lots of grass and bugs to catch, there is plenty of room for them in the 2 coops I have in the main yard. BTW the rooster is 2 years old.

 

[kmw1101]

In our original flock we have 3 roosters and 16 hens. We integrated 6 more chickens when they were 8 weeks old and had no problems. The older chickens will establish the pecking order so expect the younger hens to be very vocal during that. Also, our head rooster did go after them the first day because they were going too far away from the flock. It sounded like he was killing one of them but we all saw it happen and he barely touched the baby. They got used to each other quickly and none of our 3 roosters have ever tried to mate with the younger hens (who are now 4 months old).

 

[azygous]

Your chicks are the exact same age as mine. I have no adult roosters, but two of the chicks turned out to be cockerels.

You probably won't see any interest in mating the pullets from your roo until they reach point of lay. That's a ways off, and they should be fully integrated by then.

You just need to make sure the new kids have plenty of space and perches and other things they can fly up onto to evade any aggression from the adults. Being accepted as part of the flock has already occurred, so it will be settling into the pecking order that will be on the agenda.

It doesn't require much for younger members to learn respect and deference, a few pecks is usually all that it takes. I wouldn't expect you'll see too much conflict at all as long as your run is large enough for the youngsters to give the adults a wide berth.