Glad to know I'm not the only one that noticed that, "birds of a feather stick together" ...
Since I started up with chickens, I always get an even number of the same breed in a bunch. Once I had 3 BLRW & 1 EE, noticed the EE was always on her own, she was the Alfa & always bossing the others until one day. I saw Ruby (BLRW) go after Topaz (EE) = chicken fight like I never saw and probably wasn't as long as I thought it was. But after that, the EE never picked on the BLRWs and although they ate together, roosted together, when grubbing they kept their distance from each other. So now I make sure I keep an even number of each breed.
I've noticed that although they are all the same age, raised together and get along, they kind of stick to their own breed when hanging out. oldhenlikesdogs post makes sense although I've been told I'm reading too much into my observations.