As long as you are sure the run is predator proof. Is the exterior fencing buried beneath the ground? Even with no raccoons obvious there might be other predators. Looking back I guess I do remember we did have one or two that tried to roost outside over the years,and we always did bring them in, but it was because of fear of predators that we did. That is the main thing. Just make sure that she is safe. As far as sleeping outside in the cool weather, that won't make her sick.