My introductions have gone well. I do put the young ones in separate coop & pen arrangements, but these are still within the entire run where all the Big Chickens roam when I'm at work. I keep them in there for at least two weeks. They get to see each other, hear each other, interact through the fences between them.
Then on a weekend, when I have let the Big Chickens out to free range (but they come back in the run to their coop(s) to lay, and to eat feed or drink water), I open the pen for the youngsters and just let them come out on their own, as they gradually do.
I continue to keep feed in the youngsters' pen, as well as in the Big Chickens' coop. The BCs will go into the youngsters' pen and check out the feeder and waterer there, to make sure it's not something better than what they have been getting. But it still gives TWO locations for sustenance so the BCs cannot keep the youngsters from eating/drinking.
If a youngster gets pushy, it gets pecked and chased a couple of feet. No major chasing, no major pecking, no mayhem.
After the kids have scoped out the entire run (except for the BC's coop, which they only peek into, not enter) they eventually make their way to the open run gate and will hesitantly go "free range" a few feet from the gate.
Now, three weeks later, the youngsters tend to roam in their teen pack, but they all come running when it's treat time.
