I'm new to Sac (moved here last December) and new to chickens (3 sliver laced Wyandottes, ~26 weeks old). How cold does it get, and what kind of winter protection do the chicks need? They are in a tiny, probably drafty pre-fab coop with a screen door where they sleep - I will change the door out for a solid one, but they needed the screen for ventilation it the summer. I plan to add two 4" vents for ventilation near the roof. How cold will it get, and when? I have never lived inland, so this weather is quite a change! Thanks!