I have one flock of 3 pullets and one roo that are about 4 1/2 months old and a flock of 6 pullets that are about 2 1/2 months old. The small flock free ranges during the days and the larger flock and a large run. The run is in the area the small flock goes in so these guys all see each other everyday and have been for about 2 months. All are standard size birds, no bantams and no giants. What I need to know is; how close in size do they need to be before I introduce them? will the roo be too aggressive? or should I just give it time to work out? what is the easiest way to introduce them? any tips, suggestions, ideas??? I would like them all roosting together by winter, by the time it freeze at night, to help keep each other warm and so I don't have to go buy more heated water bowls, etc... Each little flock is very happy and content as they are, but I think they could be just as happy all together.