I have 4 white leghorns 11 weeks old. They have been outside in their coop and enclosed run since they were 5 weeks. They were staying in the run from dawn till dusk but I’ve notice the last few days they’re spending more time in the coop. They come out to eat drink and peck around then one would go into the coop then one by one the others follow. I don’t believe it has anything to do with the weather because its been beautiful out here. Could there be any reasons for this change?