We waiting like 3 weeks and then i fenced off the area under our nest boxes (7ft long, 2 ft deep, and 19in high) for them to be close to the adults but not in pecking range... After 2 weeks of that, i cut the fencing at both ends to allow the chicks to "mingle" while maintaining natural escape routes... Naturally they chase to the corners, where chick sized holes wait for them to get to safety... Once they had the option to come out, they were roosting at night with everyone else within the week... Worked well enough thats how ill do it next time... Learned from our first new chicks getting pecked raw and seeing skull on the back of ones head
Mine are raised by broody hens, that take the chicks out after 2 and before 3 weeks without regard to season. I have had 3 week olds outside with there moms in Jan. Of course the brodys look after and protect the babys. I just cannot see going back to the red light/box/my problem, when chickens raise chickens so well.
As for going outside, we started giving our chicks "yard time" for an hour a day after the first week... Supervised of course... After a couple weeks of this they got 1 hour unsupervised (ok, we peeped in on em, but they didnt know) ... By week 5 we let them spend the days outside, tho they didnt mingle with our grown chickens... But when it was time to go in for the night they go in just like everyone else... Here we are, week 8, everyone present and accounted for without incident