Its a pied, it'll simply stay that way all the way through adulthood. Many people say they have white rheas, when in fact they are a pied if they have any bit of grey markings. True whites are purely white...no grey at all. They are now hard to find because many people have bred them with greys. But if you take two pieds and breed them, you can get pure whites and breed the grey markings out easily. I only keep what I call whites, but each one has a little grey on their necks, but they're chicks come out 100% white.