iajewel is right. If both parents were chocolate, the offspring would be chocolate.
Black drake to chocolate duck:
100% black
Chocolate drake to black duck:
chocolate ducks
black drakes
I have a chocolate drake and should be lucky enough to come up with a few clutches of sex-linked ducklings!
If you breed a blue drake to a black duck you'll get:
25% blue drakes
25% blue ducks
25% black drakes
25% black ducks
The other combination will give you 100% black.
If you breed the blue drake to the chocolate duck you'll get:
the same outcome as the blue to black breeding
Here's a link to...