White call ducks-color question

[DoubletakeFarm]

I'm breeding for white calls. I have 5 male and 5 female breeders that are all white with no black on them. Just had some ducklings hatch and one of them has two black spots on his back. Does this mean that one of my breeders is throwing black, or is this something common on ducklings and will molt out?

I found this comment on color standards but it doesn't explain:

Major Faults
Both: Any black plumage in the mature bird.

Minor faults Dark specks on the bill (with age).
Both: Elements of black plumage on a young bird.

 

[learycow]

Likely means some of your parent birds are not "pure" white.
Whites can hide other color genes which in turn can recessively pop up in offspring

I would suggest pairing them and hatching that way to see if you can weed out who the culprit(s) are unless you don't mind the speckled babies.

And you'll find that those with small spots of color will molt into fully white birds. So can easily be hidden in a white flock. So be sure to keep them marked (banded) so you know who isn't a pure white

 

[DoubletakeFarm]

I was afraid of that. Now to find the culprit....not going to be easy.