Why are some of my Muscovey ducklings yellow and some are yellow and black?

Question

They are purebred. We don't have any other ducks.

Answer 1

Just their genetics.. along the line they had a genetic variance.

Answer 2

That is just an indication of their adult color. The solid yellow ones will end up as white. The black and yellow will be black and white. Chocolates hatch out as a brown and yellow. I am not familar with showing Muscovey but have owned lots of them. The colors in them are all mixed up.