That sounds like a pretty flock, and all about the same size. I had a little trouble mixing Blue Orpingtons in because they're so much bigger, especially the roos, but really, chickens don't seem to know how big they are. It is funny though how the breeds will stick together, the hens anyway...my buff orps always foraged and roosted together, the black ameraucanas did too...how do they know what they are? They all came together as day-old chicks.