My Silkies went outside to live today. They are a week old, and the brooder pen is a wire enclosure within the run. They are fine. In fact, I kept them in the house longer than I normally keep chicks inside. Usually I just keep them in the house for the first 24 hours after they arrive or hatch in the incubator. The three chicks I hatched a few weeks ago were fully integrated with the adults by the time they were 4 weeks old. I have younger chicks that just arrived last week living out there now, and the Silkies were hatched here at the same time the shipment of MPC chicks got here. I kept the Silkies in longer because they seemed so much smaller. But today they went out to live with the other week old chicks.
I'm a firm believer in not stressing chicks with a lot of change. If you take them from the feed store or from the shipping carton and put them in a brooder, then move them, then move them again, they get so confused. They are a lot like adult chickens in that they don't like change - it scares them. If you put a strange object in a brooder with very young chicks, they react exactly the same as adults do in the same situation - they get away from it as fast as they can, then they huddle together in a knot for security.
My chicks would probably kill for daytime temps in the 70s and 80s, and nighttime temps in the 50s and 60s! I'm in northern Wyoming and it could be another month or so before we get those temps. Make your chicks a "huddle box" - just a cardboard box with the open side down, with a hole big enough for them to get in. They'll quickly learn to go into it when they get spooked or chilly, and they'll snuggle up in there. It's sort of like Mama Hen - it's a place to scoot under. @azygous uses one with great success! Good luck!
Edited by Blooie - 5/27/16 at 9:01pm