i don't know about everyone else, but in all the experience i've had with chicks in the past 2 years....i've noticed that no matter what breeds i personally came in contact with...it seems like the females always feathered out faster than the males. i hatched 2 batches chicks this year and i knew i could only keep 2 of each batch (BCM and Olive Eggers). well, i feel like i'm pretty good at figuring out who is male and female when they hit 10 - 14 days old. IMO, the males don't have tails at that time, and the females are already getting their tail feathers in pretty well....and the girls look like more of a miniature chicken shape at that time and the males look kinda goofy with short wing feathers and no tails. but i would think by 6 weeks, the feathers look alot alike on both sexes...but you may be able to tell by comb size and color at this point. i have two 7 week old BCM pullets and i picked them out of all their other hatchlings when they were only 2 or 3 weeks old....gave away the rest to friends (i had about 18 of them) and sure enough, i picked pullets. i also have two 5-week old Olive Eggers and i used the same way to choose pullets and it looks like they're pullets as well. i had about 14 hatch outta the OE and i gave the rest away to friends (wish i could've kept them ALL)!!! maybe you could post a pic? maybe i could also post a pic of my girls tomorrow (if i can get hubby's help in getting the pics on the computer).
As to the Wheaten comment - You're getting feather sexing mixed up with sexing by feather color.
Feather sexing is sexing at 1 day old by feather pin lengths.
Faster growth does not work as a sexing method. I can say for one, mine certainly follow that rule about 50% of the time!
Cuckoos and Golden Cuckoos can be sexed at hatch by the white dot on their head, Wheatens and Blue Wheatens at 1 week old or older by the color of their feathers, Black Coppers at 4 weeks old by the amount of red on their bodies and their comb size, blues and splashes at 4 weeks and older by comb size and by color patterning and depth.