Where have the littles been staying up to this point in the day time? I just recently had this similar situation. I have seven 9 week old pullets. I kept them in a brooder inside the house, but around 2 weeks old I let them inside the run with the big girls and rooster in their own enclosed pen. The "see no touch" method. I did this for about 4 weeks, still bringing them in at night. At 7 weeks old, I let them out of their enclosure to run around the run area with the big girls, but keeping their pen open so they'd have their own space. I supervised, of course, and there was some pecking, but I just watched and made sure they were ok and put them back in the pen and closed it up. Eventually after a couple of days I just let it happen and let them run around at will. There was a few squabbles, but after about a half a day, the little pullets were running around like they owned the place and everything went well. I finally put them up in the big coop at dusk on the 3rd day of running around freely with the big chickens and checked them at first light. They've been doing great going on 2 weeks now and all the chickens are doing well together. Honestly, just keep an eye on them whatever you do and things will just work itself out - good luck!
