Can you tell anything about age?

[PeuAPeu]

I just bought ten chicks but they obviuosly are different ages. I can't tell if it is days or weeks difference. My oldest ones are the Australops. The youngest ones are the Black giants. The other ones are somewhere in between. Can you tell anything from my photos?

 

[bigchiefhoho]

Judging just by feathering (not by size), I'd guess about one week's difference between the youngest and oldest, but I'm no expert.

 

[lsg1007]

Agree 7-10 d difference in youngest to oldest