A few nights ago, we decided to see if the chicks would take themselves to bed. 7 managed it, 3 did not. The following night, 9 managed it and 1 did not. It has continued like that for several nights now.
The sleeping positions vary. Some nights they are all on the floor, some nights 7 of them pack on to the top of the hen. I've still been putting the hen on before I go to bed, because it gets a bit nippy at 4 in the morning.
We've tried teaching the straggler to go up the stairs, but she just isn't getting the hang of it.
Today, after I mucked out. I decided to put the roosting bars in. I don't want to force them to sleep on roosting bars though, so they also have a flat nest box as an option, plus the top of the hen. It will be interesting to see where they choose to sleep.