Which is which

[funny farmer]

These are my welsh harlequin ducklings. I was told they are male and female. At this age I can't tell which is which. Any help is appreciated.

 

[Pyxis]

My guess is right duck, left drake, going by beak color. Adult females have that black beak, and adult drakes have yellow. Then again if these are hatchery ducklings all bets are off since hatcheries don't really breed to standard.

 

[Sfraker]

I second @Pyxis Right duck and left drake based on bill color. That is how mine from Metzers could be told apart at that age.