Mine go to bed surprisingly early. I've gone out several times and get myself worked up into a tizzy because I can't find one or more of them after searching the entire yard.
Then look up in the roosts and there they are!
They generally go to bed somewhere between 8 and 8:30. Well before dark.
Wow. Sounds like mine are early birds! They start going in around 6:30PM and somewhere between 7:00 and 7:30, they are all inside and I can lock up the coop. If it's a cloudy day, or nasty weather, they are typically all on the roosts by 6:30.
We are surrounded by woods, so there is no direct sunshine on them after about 6PM - just shadows from the trees. So maybe that's why they head in so early