Strangest case of Agrarian Reform I ever heard of.
However, this is even happening with poultry.
Chickens and turkeys that are fram-raised on grain rations have more white meat, and the dark meat is lighter, than the foraging chickens & turkeys of yester year.
Same thing with pigs: ever since they switched from rooting in the garbage, and started getting fed farmed feeds, they have become "the other white meat".
Still, as Rocky Horror (Meatloaf AGAIN!?!) pointed out, humans still come with both white or dark breast meat. ;-)
It was only when early humans gave up hunter-gathering and switched to farming about 5,500 years ago that white skin began to be favoured,which is difficult to explain since it was at least 7500 years ago in Europe, and the currently known oldest (uncalibrated) RC date for multirow barley is 14,000 BP. :')