i have chicks that were hatched 10/20 and they are currently residing in my garden tub. i clean it every day and even let them outside to play for a few hours when it is nice. but i have 6- 1 week old chicks and 22 eggs due to hatch on thanksgiving. i am afraid my tub is gonna be overloaded...lol. how old do the chicks have to be before i can put them outside? thats considering this cool weather too?