Hi, This is my first winter as a chicken owner so I need some reassurance! My question is: how cold is too cold for chickens? Nights here in Salt Lake City have already dipped down to 30. My coop (although insulated) doesn't seem to stay much warmer than it is outside (I check the thermometer inside and there's no big difference). I have no plans for heating but I am concerned about these girls nevertheless. I could run electricity out and was thinking of putting in a radiant heater panel. I don't put in extra lighting since I believe in giving the layers a break during the winter. Please let me know if they are going to be alright when the nighttime temps dip down into the teens or even single digits!! Thanks so much!!