Nublette With a Stupid Question (Red Dorking and BCM)

So, please - no yelling at me.

I've been considering adding BCMs and dorkings to my mix. I wanted to keep them separate for breeding purposes and so I've been gearing up to build their areas and just investigating which type of dorking I wanted.

As I looked into dorkings and saw the red ones, I kinda got curious...I know the builds are totally different, size and the tails are absolutely different....but, they sure look like they share some of the same genetic stock with black copper marans somewhere back up the line.

I'm curious about the history that is known about the breeds and if there was a crossing at some point that brought them to separate breeds?

I've tried to find information on it on my own; but, my google-fu is failing me.