I have 16 chickens. I got them in 3 different groups. My oldest and the first I got are 12 weeks old, and there are 6 of them. The next group I got are 6 weeks old, and there are 6 of them also. My youngest are 4 weeks old, and there are 4 of them. Still with me? lol The 12 week olds and the 6 week olds all free range peacefully, but they stay in two separate groups. They never range together, but they two groups will range side by side frequently throughout the day. I let my 4 week olds out for a little bit this evening and the 6 week olds came over and hung out with them for a bit. They got along well (I keep the youngest ones in a tractor in the yard so everyone can see each other) but eventually the 6 week olds went off on their own. Will they ever all range together as one flock, or will they always stay in separate groups?