This is a good time of year to inquire at you farmer's co-op or quality farm suppy store about a thermo-plug. It is a plug that goes into a standard wall socket (if your coop has electricity). When the temps fall to 34 degrees, the turns on the heat lamp you had plugged into the thermo-plug. If it isn't in stock they will know that you want it for the upcoming winter. Our last two winters in the Pacific Nortwest had severe cold snaps for 1-2 weeks. My coop is uninsulated and just fine for 340-360 days of the year. The very coldest nights could have been seriously harmful to my chickens because they were aclimated to milder cold temps. The thermo-plug was sure handy and I didn't have to plug and unplug my heat lamp. The lamp also came on when the temps dipped below 34, as we had several weeks of hard frosts but milder days. The light didn't seem to bother the chickens due to the incadescent/"infrared" nature of the bulb. It helped keep them comfortable and unstressed and they kept laying eggs. A 125 watt heat lamp in at 10' X 5' X 9' high coop kept the chickens comfortable during even the coldest nights. Just an idea, as a thermo-plug isn't all that widely known.