I let my big ones mine free range and they always go in right before dust..... My 2 little ones are 4 wks and still in garage but I take them out and let them free range... When they get tired they go stand by house and squawk. lol. I agree that if they've lived in coop for a week or so they will go back in at dark.
If they have been sleeping in the same place for 4 weeks now they should return at bedtime. If you are nervous for the first time perhaps let them out in the evening an hour or two before bed and sit in the yard. That way you can watch them go home when its time and they don't have all day to wonder.
I always watch mine go to bed at night... Lol. I'm sure my neighbors are like she's crazy!! Oh well, they are entertaining!! Lol... When my last one goes in which is ALWaYs Daisy the BO, I close the door so she won't change her mind and come back out... Haha