Hi there, we were given 4, chicks at 3 weeks old (we think they are Isa Brown) and have had them for 2 weeks, so now they've hit 5 weeks. Today we went and picked up 4, 15 week old chickens (Hy-Line) and put them in all together. What a mess, the little chicks went running, because the 15 week olds kept pecking and raising their tallons at them. Now I realize there is a pecking order, but this was really disturbing. We spent most of the day when the chicks were out scratching, on yard duty for their protection. We've put them all to bed now, in the same coop, the chicks in a cage, with feed and water and the older chickens having the run of the coop. If there is anything I can do, to aid in assimilation of a little family, I'd sure appreciate it. Until then, we're going to keep trying to get them to tolerate each other.