I have been reading these message boards, and other sites, for a couple of weeks. I even got a book "Raising Chickens for Kids." The message boards here at the coop have been by far the most useful :)
I am getting 11 staight run dark brahmas, 8 americaunas (4 pullets, 2 cockerals), and 6 barred rock pullets today in the mail. This is my first time doing chickens. I'm wondering how old these gals, and guys, need to be before I can put them out into an unheated coop. SSG

Start them at 95 degrees under their heat source with room to get away from it to eat and drink. Each week, drop the temperature 5 degrees until you get to 70. After that they should be feathered enough to be on their own in a moderately cool coop. Watch them for signs they are cold (piling) or hot (crowding into the corner furthest from the heat). Their behavior will tell you a great deal about their comfort. Good luck.

Steve,
Dr Smith is right, but I think you can decrease temperature more rapidly, depending on how quickly they feather out. Just make sure that they are not "screaming" loudly, cause that's a sure sign they are cold. You are new at this, so be careful, but at the same time, you are not affected by conventions just yet, so you might find something that we did not think would work, but it actually does. Good luck.
ARam