I only know that Murray McMurray Hatcheries sell the Black Stars, Red Stars and Pearl Whites as 17 week old pullets.
Also that Meyer Hatcheries sell Golden Buffs, Black Stars, and White Leghorns as started pullets.
Moyers in Pa sells Brown egg layers- see the following I copied from their website....
Moyers Brown Egg Layers are a hybrid cross between a White Rock egg-layer type female and a Rhode Island Red male. Sustained production peaks of months over 90% are the norm, producing 270-300 eggs by 72 weeks of age
Good Luck...
Lisa