We had a Barred Rock go Broody and she hatched us 7 little chicks. They are 2 weeks old now. When should we start letting her take them out and around the Yard? We will supervise of course? Also, right now they are in our basement in a cage, when can we move them to an unheated out building? (Nights get down to just above freezing) Will the Hen keep them warm? We have other chickens and a rooster in the yard to, will they bother the new chicks?