Voice changing?

[EnglishSpot2003]

Is 2 weeks a normal time for voices to start changing? One of my runner babies is starting to sound a little different.

 

[petchickenlover]

I've head people say that their ducks have started quacking around 2 weeks, some one said it took theirs up to 8.. mine are 1week,2weeks, and 4 weeks and none have started quacking yet.