When mature?

[tiffanya]

I know the age that a chicken hits maturity varies by breed but I was curious if anyone has a good reference that tells the ages for each specific breed? My hens are all laying, but I wasn't sure if at 10 mos. they are all at "top weight". In particular I was wondering about Sussex and Orpingtons.

 

[Dingleberry]

my orpingtons were full grown i believe at 9 months