Finally finished the coop, yahoo! I moved the chickens out and they've now spent 2 nights out there - with no heat lamp - lows have hovered around 42 to 45. The majority of the chickens are 7 weeks with some at 5 weeks too. There's a stretch of 3 nights coming up with lows around 31 to 33 - after that stretch, spring kicks in and lows should be 50 plus. I'm wondering if I need the heat lamp for the few nights in the low 30's??? Would hate to lose any chickens after getting this far...thx!