Both strains have now been internationally recognized following selective breeding, propagation over several generations and close observation that their special characteristics have stabilized.
這兩種品種在選育出來以後，以多代繁衍觀察，令特徵、性狀穩定，經國際認可「定名」後，才取得文憑，成為被珍藏的一員。比較特殊的是黑色番鴨。