It doesn't work on pieds...Ziggy still has bars and he's had his molt.with my pied she's got bars on the under side of her tail, that you can see very well, and i was told that's how you tell the females on the mutations you can't just look at and tell if it's male or female, my female white face has those same bars, and so does my pearls and my one i'm not sure what she is lol