If it's protected, they will be fine. My hens always slept inside the coop until I got guineas. The guineas started sleeping on the roof and all of my hens decided to join them. Since it was enclosed, I didn't worry. They even insisted on sleeping there when it snowed!!!so my girls are almost 10 weeks old and they are absolutely determined to sleep on top of their coop at night. when they were younger they would sleep inside but since they were about 6 weeks old, they want to sleep on top of the coop. i’ve tried putting them inside at night but the opening in the coop where the ramp is does not have a door to shut. any ideas?