I’ve found that old timers love to talk fowl. I don’t ask many questions, I listen. Every state in the US has quality gamefowl and gamefowl breeders.
If you want to breed them well, it would be best to stick with fewer strains, and have several pens/coops, in order to rotate accordingly and raise enough from one strain so as to properly select the next generation. Natural selection is a useful tool for me but cannot be relied upon. Hens also use sexual selection, particularly when free range. It’s your job to observe and select what you want out of each clutch. Cull undesirable fowl in cycles as needed.
Over here it's slightly different, but I will not go into details.
Great information