Not breed or gender, but age?

[jjhere]

We just picked up our chicks a couple of days ago and the guy at the feed store said they were all "about a week old". This one is quite a bit bigger and "featherier" than the other two (she's also a different breed tho) and I'm thinking she must be older. She is an Ancona.

Thanks!

 

[Illia]

She looks to be 2 weeks old.