My older group of chicks has been in their coop for 3+ weeks now, and have been free ranging for at least two and always gone back in the coop at night. Usually a lot earlier than I expect (sometimes as early as 6:30 I've gone in and found them roosting already and it gets dark here around 9:30 or 10 right now). My younger group has been out in the coop for about 2 weeks and actually free for about a week, and again, have always been back in the coop by dark. Often earlier than the older group. Tonight, I went out around 8:00 to close up the coop and was surprised they were all still out, wandering around, pecking at grass, etc. They seemed happy, so though I made a half-hearted attempt to shoo them all into the coop, I decided to leave them and come back after I'd put the baby down. I went out again around 9:30, almost completely dark, and the older group of chickens were all huddled together on the top step of our deck. I thought that was really odd and grabbed a couple of them to start taking them back, and realized the younger group were all huddled on (and under) the bottom steps. I put them all in the coop (on the roost, which hopefully is okay, the younger ones haven't actually started roosting yet, I'm hoping the Silkies will be able to get down in the morning), two-by-two, and they were all there (though I couldn't find two of them at first, but they were just fast asleep and not peeping until my hand managed to make contact with one of them under the step). I went back out with a flash light and searched the coop to make sure nothing was hiding in there that would have spooked them. Got the stink eye as I shone the light near the sleeping chicks. They were all amazingly calm as I picked them up to bring them to the coop and settled on the roost quite happily. The room where I put the baby down is right over the coop and deck stairs and normally if something spooks them I hear it pretty clearly, and I didn't hear anything at all. Both the run/pop door and coop door were open because the younger group haven't quite figured out they have to go in the run to get into the coop yet, so it's not like they were locked out. They don't really like each other yet and don't mingle, so it's odd that neither of the two groups were in there. I don't get it and now I'm a bit paranoid about letting them free range again. At least this time they were right by the house and I couldn't have missed them. I'm on an acre and a half though, if they chose to roost in the woods I'd never find them.