So, I had the 4 youngsters sectioned off inside the run where the 4 bigger girls are. However, they kept escaping and they've been running free in the run all day now. I've gone to check on them a few times, and so far it seems as though everyone is behaving themselves. Perhaps because our run is so big that they stay out of the big girls' way? Our run is huge...at least 1500 sq. ft. Or is it because the older pullets aren't full grown yet...so maybe aren't as territorial? I think one of the younger ones is a roo, but I'm not 100% sure yet.