Conversely, two of the Hawaiian islands, Oahu and Kauai, have unintentionally become laboratories of chicken de-evolution.
Two hurricanes broke apart their coops and allowed them to run free in their respective jungles. Generations later they have become fully feral.
Hawaii’s feral chickens are, today, a genetic blend of Jungle Fowl, fighting birds, and a host of domestic breeds. Mostly they look like Jungle Fowl. They are small, quick, and adaptable. And quite noisy.