Hi all - I have a brood of chickens that my husband and I are raising. The age range of the chickens are 10-18 weeks old. How come the older chickens go inside for the night, however the young'lings will stay all grouped together outside the coop and won't go in. Each night before we go to bed, my husband takes each chick and hand delivers them to the coop to be sure all are inside. Once they are in - they stay. I don't get it... help? Will they figure it out...?