What gender of blue Swedish?

[Duckwrestler404]

I got these ducks from my local feed store and really want to know their gender and tried vent sexing them but I just can’t and wandering if you guys can help me figure it out

 

[Isaac 0]

Unless you vent sex, you will have to wait till they are 4-8 weeks old and voice sex them, males will make a raspy peeping noise while the females will do the occasional quack.