Two questions: We have a run that has a contractor's sand base of about 4-6 inches deep. Do we need to supplement with grit? What is an acceptable night time temp in the coop. We have a heater that kicks on at 36 degrees and turns off at 45 degrees. Is this warm enough? We are in Bozeman, MT where it can get very cold even in the daytime. Is there a temperature that should be maintained for their well-being or do they adapt to the cold climate. We have 3 buff orps, 3 slw and 1 banty barred rock.