Chicks voices changing already??

[Roger98]

I have 2 Cuckoo Marans, 2 New Hampshire Reds, and 2 Easter Eggers that are now 6 weeks old and they all sound like they're hoarse and their peeps aren't as high pitch as they usually are but they seem healthy and normal. I don't remember my other chickens voices changing this early, should I be worried? The first one I noticed was the one EE girl that started before everyone else... I feel like it's probably nothing and I'm over reacting (I do that a lot) but I want to be sure

 

[LittleMissCountry]

I am new to chickens but mine started changing their peeping pitch around 7 weeks. They are 9 weeks now and sound more like hens than chicks.

 

[SueT]

6 weeks, they're big chickens now. Mine began at 4 weeks...