Not sure if this is the right forum for this, but this past few weeks we have been seeing temps drop into the -20s F and, with windchill, -30s F and -40s F. My coop is insulated, but not heated, so it has been hovering around -5 F inside. My chickens are doing fine, but on the few days per week I don't work from home I come home around 4pm to find frozen/cracked eggs. Sometimes the cracks are just hairline, and once the eggs warm up inside the cracks close up. But lately with these really cold days we have been having the eggs are frozen solid and have wide cracks in them (that begin to seep once they warm up). I'm contemplating hanging a heating lamp inside the coop (my coop has electric outlets inside mounted up high) on really cold days. Anyone have other suggestions for not loosing eggs to the cold when you aren't home and available to check the coop? I have an externally mounted nesting box (see picture below) that is also insulated on the inside. Thanks!