You might get something useful from my two posts in this thread.
https://www.backyardchickens.com/t/...t-age-chickens-and-giving-them-the-right-feed
For people that don't think the extra calcium in Layer can harm their chicks, I'll offer these studies, one where they started the Layer at hatch and one where they switched to Layer at 5 weeks. I've heard various things about what age it is safe to switch to Layer but I haven't seen anything that specifically studied that. I suspect there is not one "magic" age for every chicken in the world but will depend on the chicken and how it is managed.
Avian Gout
http://en.engormix.com/MA-poultry-i.../avian-gout-causes-treatment-t1246/165-p0.htm
British Study – Calcium and Protein
http://www.2ndchance.info/goutGuoHighProtein+Ca.pdf
If you house them somewhere for a week or so, they associate that with home and should return there every night near sundown. The only exceptions I've ever seen was where either a bully beat them us so bad they did not want to go into the coop or for some reason they want to sleep just outside the coop. In either case, they sleep very close to the coop. They still associate that area with home. It's not hard to find them.
Something I regularly see. My grow-out coop is about three feet off the ground and has an 8 x 12 run attached. When I move them from the brooder to the grow-out coop I leave them locked in the coop section only for a week or more. When I let them out into the run, several or sometimes all usually sleep at the foot of the coop outside in the run next to the opening. They are not roosting yet. I think what is happening is that since they are not yet roosting they look for a low place sort of protected where they can huddle for the night. I have to physically move them from that spot to inside the grow-out coop for them to get the message. I've had chicks that got the message after one time and I've had to do this for a couple of weeks for some. Some sleep in that coop from the first night.
As I mentioned in that other thread, I usually wait until they are 8 weeks old to integrate them with the adults. I don’t wait that long so much for a size or age thing. Sometimes that’s just me busy with other things, but it’s usually that long before I’m comfortable that they will go into the grow-out coop every night and not try to sleep by the door.
I’ve had plenty of broodies raise their chicks with the flock and wean those chicks before they are 5 weeks old. I have lots of room during the day and on the roosts at night, both of which I think is important. Those chicks avoid the adults because the adults will pick at them if they invade their personal space, but I have not lost one yet to the older hens. Age does matter, but if you have space, they will generally work it out.