Hi everyone, this is my first year with chicks (we usually buy laying pullets in late spring and give them to a local farmer when it gets cold). My "babies" are now 9 1/2 weeks and I am nervous to leave them in their coop full-time. It is still dipping down to the 20's at night here in WI. They are bantam Cochins. When are they big enough to stay outside at night? I put them out during the day currently.