I know for the most part that chickens can handle cold rather well especially if they are a cold wheather breed (mine are). The question I have, once the temperature gets into the teens and lower, should I use an electric oil heater to take the edge off? I also know that I do not want them to become accustomed to the heat incase we loose electricity and the cold shock factor to their system can be dangerous. My coop is a well made coop but I failed to insulate it prior to this cold wheather season. I am still new to this chicken game and this is our (chickens and mine) first winter here in Northwest Arkansas. I have two windows on the coop which I leave open just a crack to allow fresh air in through the coop. Helps to eliminate respitory problems. The entire floor along with the nesting boxes are lined with about six or more inches of wood shavings (not cedar). Eventhough I am using an electric water heater plate to keep their drinking water from freezing it still forms a thin ice topping that I have to either break or I add warm water to the 5 gallon waterer to melt the fresh icy water inside. By the way, my nine hens (had 11 but lost two due to a fox and red tailed hawk) are laying really well, I am averageing 6 to 8 eggs a day. I do however use an automatic 60 watt light in the coop that comes on at 0300 each morning. Any comments would greatly be appreciated. After all, I want to keep my hens as comfortable as possible without spoiling them.