Starting this summer my hens began roosting outside in my enclosed run (I assume because it was so hot and humid at night). I kept the coop door open 24/7 because the run is 100% secure.
Winter has come and they haven't moved back inside.
I'm inclined to do nothing because the run is secure, I don't have to deal with opening the coop door early in the morning, and it's a lot easier to cleanup poop outside of the coop than inside.
But is there a point that it gets so cold that they need to be forced backside to protect them from frostbite or exposure? Or will they go inside on their own if it gets to that point? Where I live it rarely drops below 30 at night, but we'll get a few hard freeze warnings a year — so it's certainly not all that cold of a winter, but technically sub-freezing. One thing I worry about is that it rarely hits freezing during the day. When the chickens go to roost it's usually in the 40s, so if freezing was a cutoff point, for example, they wouldn't know it's going to eventually be that cold.