I can't help but be amazed at all the posts of people deathly worried about their chickens and cold weather. Has anyone ever actually lost a hen they could definitely attribute to cold? Where the hen was in a dry coop, adequately fed and watered? For all the hundreds of posts of people using heat lamps and insulation and buttoning up their coops air tight, I can't recall anyone actually losing a bird. I think people are wasting a lot of time, energy, and money on combating cold. Even worse, I think they are imperiling their hens' long term health by not having adequate ventilation. I can't find in any of the agricultural literature the need to even worry about chickens until the temp. is below zero (Fahrenheit), sustained. Domestic chickens predated electricity by thousands of years. Did the pilgrims build fireplaces into their coops and keep fires going all night? How did they ever keep the species going when all their chickens froze solid every winter? Why don't we all give the local utility a break (although they probably love people running 150W IR lamps all night), and chill out. I'd wager more chickens have been burned to death from heat lamps than have been frozen to death from the cold on this site.