I just put my 9 week old, one 3 wk and two 4 week olds outside today, permanent move to the coop. I love them dearly, but their messes have gotten ridiculous. They enjoyed their day scratching and hunting bugs- and went into their coop on their own.
I put the ceramic heat emitter out there, though. It will get down to the 40s here tonight, and the youngest arent fully feathered. They will be warm and the coop is roomier than their pen has been. I am sure they are going to be fine-but I do worry about them. My husband told me I should get a baby monitor out there so I can listen to them.
I will go check on them one more time before I call it a night- but it sure is hard to put them outside, isn't it?