All males?

[flockman]

I have 4 Pekins that are 7 weeks old. None of them quack. I thought that they would quack by now if they were females. I can hear 2 males and 2 that still peep. I would guess that they are all males right?

 

[learycow]

They are still too young to voice sex. They go through a "puberty" stage where males and females can sound similar, and even be confused with one another.
For voice sexing that is accurate, I would wait until they are at LEAST 12 weeks old. Some will change around 10 weeks but 7 is still too young