ours were just 5 wks on Friday, and they are also out in the coop ~ Of course, I am in Idaho, where the temps fluctuate from 73F one day to snowing the next ~ but, out to the coop they went anyway, too crowded in the brooder.
Also, On every single warm day above 50F, I put the chicks out in the sun for a few hours, in another little "playyard", so to speak. I believe this has helped them to feather out early and well ~ my chicks look like a lot of the pictures on this site that say their chicks are 7 to 10 wks old.
I was inspired by Ruth, with her journey through a Different Way thread, and liked the idea of being a little more natural about the whole thing. I think a mama hen would parade her chicks around in the sunshine, early spring, even if the temps aren't precisely what all the books say they ought to be. I did tend to be right there with them the entire time, however, and the moment any started their loud "I'm cold" cheep, I hustled them back inside.
Still, I think they have done rather well with it, and they surely do LOVE being out there now ~ bonus, they have FINALLY figured out to go back up into the coop if they are getting cold ~ ALL on their OWN ~ YEAHHH!! It did take a few days of constant monitoring, to make sure they were put up into the coop once it started getting too windy & cold for them, but they are old pros at it now ~ {:>)=
~Red