So after lots of good advice from you folks, yesterday we oficially introduced our 5 almost-5-month-olds to the 11 1.5 year olds in the coop. I tried most of the tricks I learned here. They had been introduced before on neutral turf. This time I let the 11 oldies out to free range and put the 5 youngsters in the coop to scout it out and find the hiding places. I also put the feeder and waterer from the baby coop into the big one so they'd have something familiar for food and drink. After an hour or two I brought the 11 back in and stuck around to make sure there was no serious damage, and gave out lots of treats to both groups. They seemed to do well. A few squabbles, but the rooster with the youngsters has made clear he won't take any bullying, which helped a lot. In the evening, the 11 went to their normal roost inside, and the 5 found a perch up high in the run. After dark I snuck the roo into his garage night-house (neighbor issue), and snuck the 4 youngsters into the coop roost on their own end with a few feet of free space from the other 11. Everything stayed calm and sleepy until the morning. I put the roo back in earlier than normal so they could all wake up together. The squabbles have pretty much stopped, but there's very little intermingling. The roo keeps the other 4 new ones together, and the other 11 sort of stay on their own too. There's lots of room in the coop and run, so they can stay separated as long as they want I guess. Thanks again everyone, looks like we made it! I do have another question, though. Is it likely the two groups will stay separate, or will they ultimately become one flock? Will the roo likely keep to his 4, or will he start working his way into the other group too? In the beginning some of the older hens tried to challenge him, but now it looks like they're all afraid of him. It'd be nice if eventually he started leading the flock as a whole, but if they stay separated, that's not a major problem. Thanks!