Hi! we tragically had a fire in our chicken coop last winter. We have a new flock that we have had in a temporary coop while my husband builds a new coop that is just about ready for our girls to move in. We live in New England and my husband thinks we should get a heater for the coop for really cold days but I am hesitant. Of course I want to keep the flock from freezing on really cold days but the thought of putting a heater is so scary. I have ready a bunch of reviews and even though the have an overall high rating, there are many that lost their flock to a fire or smoke inhalation. Can you please comment on what, if anything you use to keep your girls warm on exceptionally cold days? thank you in advance!