blue ducks can have black spots on them (sometimes called ink spots). There's nothing wrong with your duck, it just doesn't have not "perfect" coloration.
Interesting... I got my blue as an adult, so don't know what he looked like as a duckling. He has fathered some ducklings but the females are fawn and white and buff. I don't remember any dots though. Hope someone can help you.
My Rner that died was covered in black speckles and white speckles, she was very pretty. I also hathed out 3 blue runners and sold them at 3 weeks old, the peole brought them back after 4 weeks unwanted and they were a mass of blue and plack splodges..I think its pretty..some dont
So why aren't these splash ducks? Is the genetics for getting blue in ducks different than in chickens? Wouldn't they still come out blue black and splash? Splash isn't a fault in chickenland.. why is it a fault for ducks?
The blue dilution gene's expression is highly variable. Some ducks will be dark or lighter than "normal" and some will have spots despite being genetically "blue"
I have a blue Runner drake in with F&W, brown, blue, silver and lavender femailes. This is what i got from my hatch this week...(back) lavender, blue, silver, (front) black, blue bibbed....a multitude of blues thru out the ducklings apart from the black. The blues and blue bibbed with probably have black and white speckles thru them too.