Usually once they are fully feathered you can move them out. Mine are 8 weeks today and we just moved them out 2 days ago. I have been a nervous wreck because the weater just changed. It's been really cold at night. But they have been doing well.
Depends. I started my chicks outside, in a draft free shed. By two and a half weeks old (late April) they were living on the screened porch, with their heat lamps and a draft guard and doing fine. We took their heat lamp away at 5 1/2 weeks (mid-late May) and they were very close to feathered out.