I just integrated 13 10-week olds into a group of six older ones (maybe 8 months old - they've been laying for a couple months). It went really well as far as I can see - no blood shed or relentless tormenting. We put up another 2x4 roost in the coop, with the small side up for the littles, and it's about 6 inches lower than the main roost. The bigger girls have ignored it completely until the littles moved in. Now the one that is lowest on the pecking has decided to roost there and won't let any of the littles on it. So they huddle in a corner instead of roosting. Will she let them roost eventually - I mean soon, not when they're bigger and can assert themselves?