When do ducklings start sounding different?

[Frenchie]

Hi all, my 2 ducklings are about 4 weeks old I think, they are half feathered, and one is starting to sound different. My one ducky still 'cheep cheeps', but the other little guy is now stRting to quack but it's a low quack, almost like a frog's ribbit....I didn't think their voices changed this early? When their voices start to change, do both females and drakes make the low quack or do I for sure have at least one drake?
I just think it's odd that one is making a low noise, and the other duckling is still 'cheep cheeping'?
Btw, I love this site! I have had so many questions answered on here, you guys are the best!

Frenchie, a ducky newbie

 

[Bird Brain]

Oh, good question. I hatched 1 duck last Sat and its my first. IDK I hope someone does though.

 

[xfilesnumber1fan]

My 6 baby mallards were fully feathered at 8 weeks and I could tell male from female 3 quacked and 3 didnt...

 

[One Acre Wonder Farm]

some of mine started quacking around three weeks old. You could try picking one up, if it quacks loudly, its a girl! My mature drake definitely sounds like a frog compared the ladies' loud quacking.

 

[rainplace]

My runners and swedishes are will be three weeks on Monday. Both of the swedish have begun quacking. Not all the time, but often. I didn't think they started so early either.

 

[Frenchie]

Thanks! I just put them up for the night, as I picked each up they both squeaked, I guess the one is just starting to change his sound, they don't like me very much unless I have peas!!