Duck Sexing @ 5-6 months?

[DuckBoy323]

I got four ducks 2 pekin and 1 male rouen and i believe another rouen but not sure if its a female or male cause the other day i saw it top one of my Pekin's

so i thought it was a male, and when i i first bought it, it was said to be a blue swedish but I figured it wasn't, so is there a way i can tell if it is a female or male and if its a rouen?

 

[njduck]

if it is a hen and at that age i most surely will quack and mne quack everytime they see me wanting more goodies

 

[DUCKGIRL89]

:Welcome