I checked out (they are giving me a borrow on it.) a plastic bin from my local hardware store, it is 4'x3'x4' I put in locked down heat lamps in it to keep bigger chicks warm. and put them in our shed. I can close the doors to keep out predators. They are out of the house. chicks are 4-6 weeks old. temp is 80/85 under the lamp. If they get cold the can get under. they can move away if too hot. in pic they are not under lamp because they are eating.
My new babies, hatched out by one of my Buff Orpingtons. Have 2 full Silver Laced Wyandottes, 2 Buff Orpington/ Silver Laced Wyandottes and an Easter Egger wyandotte