Rarely to never. They get to go outside whenever they want to. And they don't need heat. When allowed to acclimate naturally, they grow down under their feathers and POOF! They have a nice down coat to wear all winter long, inside and outside. I will close the pop door when it's double digits below zero (Like -15 or colder).I have good ventilation I also have power to the coop if I needed to add some radiant heat and I also purchased cold weather Hardy Birds. But you're right we do have winter in Maryland.... We don't have snow on the ground too much it happens but it goes away pretty quick
I would search this before next winter comes but since we're already talkin At what point do you cut access off to the Run for the chickens? A certain temperature?