Night is different. Chickens roost and tuck their feet into their bodies. They fluff up to trap warm air. Insulation city.
A drop at night from 20°F to 10°F? They barely notice. But a sudden drop from 50°F to 20°F? That stresses them out. Gradual changes are easier on their little bodies.
So don’t panic if the forecast says a chilly night. They’ve got it covered—as long as their coop is dry and draft-free.