First of all, thanks to all who have posted about this topic. I've searched and read as much as I could and tried to adapt that to our situation. So far things seem to have gone pretty smoothly with only a few bumps. We have two RIR's that are a year and a couple months and two 15-week olds (one Buff and one Barred Rock). When it was time to move the little ones out of the house, we fenced off half of the run and my husband built them their own mini-coop. The older girls still could go in and out of the main coop to free-range in the yard and although they squalked a bit at the newcomers and tried to peck them through the fence, they seemed to get used to it. We kept that arrangement for almost two months and finally felt that the little ones were big enough to hold their own. They sounded like the older girls too (no more chick peeps). We began the process by locking the big girls in the coop/run and letting the little ones out to free-range and get used to their surroundings. We did this for about a week, then finally got ready to put them together in the big coop at night. We went out in the dark and tried to move one, but they weren't as "asleep" as we thought they'd be and it was all kind of awkward, so we "chickened out" and moved on to plan B. In the morning, we opened the run and just removed the divider. There was a little bit of chasing in the yard, but plenty of places to run away so the first day together wasn't too bad. The first night the little girls slept in their own small coop, but by the second day, the little girls were perched and slept in the big coop. The only problem(s) thus far are 1) the little ones aren't sleeping on the main roost but in the second nest box (luckily the big girls both use the same and other nest box) and thus pooping there. I hope this will eventually change when they see what the big girls are up to in the next nest box. 2) The lower ranked of the two older RIR's just kept squaking at the little girls until it got dark enough that either she couldn't see them anymore or fell asleep. This, too, I hope will settle down. Our Buff seems to be at the bottom of the pecking order and though I've seen no pure attacking of her, she is quite timid and had just a drop of blood on her beak this morning. I hope this might be helpful for anyone planning the same process with a small flock. I don't have any pics yet of the four together, but here are one of the original outdoor set up and my very favorite from when we first got the little ones.