I slowly transition them:
- inside with lamp on 24/7
- inside with lamp off during the day
- inside with no lamp
- their own area inside of the barn
- general population
Can't give you exact lengths of time for each step because they don't all hatch at the same time so different ages get mixed together. I would guess about 3 weeks on each step inside and then by themselves in the barn until February, then mixing with the older birds.
I've found they seem to get addicted to the lamp if you don't cut them back. They will cry for it when you first turn it off, which is why i start by turning it off during the day when I'm not around rather than at night when we all want to sleep!