Quacks starting at different times for same age?

[indianaducks]

I have 10 ducklings that are all just over 6 weeks old (6 weeks and a few days depending on how old they were at the store). I'm fairly sure 5 of them are quacking - started about 2 weeks ago. The others (3 runners and 2 magpies) are no longer making the baby peeping sounds but aren't really quacking yet either. Should I assume by 6 weeks plus a few days, that they are drakes then? Or give them more time? I didn't know if I should expect multiple weeks in variation for quacking to begin if they were female. I can try to get a video of some of them later today or tomorrow.

 

[JacinLarkwell]

I would give time. I'm not sure about ducks, but chickens the same age can have a big difference between the first's cluck and the last's cluck

 

[KaleIAm]

I had variations.

 

[Ratchnick]

If They are not making baby peeps they are probably drakes. You can tell by volume, the ducks will put your ears out and the drakes are not very loud.