When it's time for bed, a group of young chickens makes a what I describe as a gathering call. A repeated series of soft but rapid "peeeeep peep peep peep peep" seems to mean "let's gather together and go to sleep". It takes a few minutes for them all to get situated and as long as they are not disturbed they will quiet down and eventually go to sleep. I think this might be what you are seeing your youngsters do. The one that takes longer to settle may just be more active than her broodmates.
If you haven't introduced a roost for them to use, now would be the time to do it. I'm a big proponent of offering a perch for chicks on day one. I believe it's important for them to roost off the floor.
I hope this helps!
If you haven't introduced a roost for them to use, now would be the time to do it. I'm a big proponent of offering a perch for chicks on day one. I believe it's important for them to roost off the floor.
I hope this helps!