I had 4 girls all 15 weeks old- 2 Leghorn, 1 White Rock and 1 Buff Orpington. I live in a suburban development on about 3/4 of an acre. I have a coop with a run and also have an 8x8 fenced in pen built around the coop. The 4 girls free range a bit under supervision only and are pretty easy to round up when playtime is over. Today I got 2 additional pullets- 1 Barred Rock and 1 Easter Egger both 13 weeks old. I put them all together for a short time tonight and it didn't seem to go well. The Barred Rock flew the pen- I chased her around the neighborhood for a half an hour. One Leghorn flew into a tree and eventually the Easter Egger flew over the fence as well. It was a temporary nightmare. For now the Easter Egger and the Barred Rock are in my garage for the night in separate spaces because when I put them together the Rock was pecking the heck out of the Easter Egger. Suggestions?? I am feeling a bit overwhelmed. I am new to this chicken thing and I didn't even think that these kinds of things would happen.