When do their voices start to change?

[sheaviance1]

I am completely new to raising chickens. I have buff orpington pullets that are 2 weeks old. This morning, one of their "voices" have changed. It sounds like the mewling of a kitten instead of the peep of my other ones. I have observed this chick, and she acts normal and healthy. I don't want to panic over something that happens as a result of growing up, but yet, with her being the only one who is no longer peeping, it makes me concerned that she is sick.

 

[Happy Chooks]

Does the chick seem to act fine? Eating? Drinking? Any other symptoms?

I've never noticed my chicks voices changing until around 13 weeks. Other than an 11 day old in the brooder that started to crow, they're still peeping like normal. I have 11 week old pure ameraucana chicks and they're still peeping also.

 

[sheaviance1]

Other than her voice, she seems perfectly fine. She just sounds different. She is eating, drinking, pooping, scratching around like she always has. She isn't sleeping any more than she did before, just sounding different.