I have 15 barred rocks about 12-13 weeks old. I want to incorporate 7 RIR (9-10 weeks) into the main flock. They were raised as chicks side by side in a very large plywood cage separated by plywood. Right now the two flocks are both in the coop (3 days) separated by 5 feet of bird netting. I also have a covered wired outside run, but it is accessible only by the b. rocks. One of the RIR's has flown over the netting and faired fine until roosting time when it got pecked and I rescued it.

I have read to wait a week with the side by side then introduce them into the main flock one by one. Has anyone had experience with successful incorporation? Would it be better to do it in the outdoor run or in the coop? (Both are 10X12) Any suggestions?

Marsh,
I don't think it matters where you have them side by side, as long as they can see each other. Of course, during the day, most chickens like to be outside, so that might be better after all. Do this for about a week and then put them all together, making sure there are places where the younger ones can hide if they get picked on. There's going to be some pecking to establish the peck order, so don't be overly alarmed about that. The younger ones are probably getting into trouble at roosting time because at that age they are still trying to snuggle up or get under each other. They'll learn which ones to leave alone quick enough and snuggle with each other, instead. Good luck.