I did a post on this the other day, we let ours out, and they come and go as they want. Even open the run. At first I was nervous, lots of predators, but, just as expected, they run to the woods, or down the driveway, but they come back at sunset, rain or not.
My flock are all weather birdies.... rain, wind, snow, ice, sun....they are out in it. If it gets too bad they take themselves inside.
Only time they really dont want to come out is if it is pouring hard, or its very windy out, or a lot of snow/ice on the ground. Otherwise they are out playing having a grand old time.