I have seen it be true that birds of a feather do indeed flock together.I've seen too many posts on this forum about hens bullying fellow flock members. Mostly those from a different strain or breed of chicken. KISS is the best strategy if your just starting out with your first flock of chickens.
But the bigger issue regardless of breed comes during integrating groups of different birds that LOOK different who are different AGES. But also see plenty of dynamics among the sames.
For me, having variety in the beginning is KISS... so I can tell who's laying or not and blah blah.
