I keep chickens. I have 4. Two are black, two are speckled. They’re not related as I got them from a hatchery. They were raised together.
When they range, the blacks hens pair off and the speckled too. When in the coop they commingle but when let out with more room they will always be with their own kind.
From an evolutionary standpoint this makes sense to me and find nothing wrong w it.