So, the girls have been in a brooder coop for the last 7 weeks. I'm in Northern Colorado and the temps can fluctuate quite a bit. In the brooder room, I had a space heater and it has been gradually lowered 5 degrees every week since they were tiny. Now I am at 60 degrees and they are fully feathered, they love being outside- but some nights the temps get into the high 40's and I am afraid the temperature fluctuation is going to be bad for them. I used a ceramic bulb in a heat lamp for the last few nights (since they have been in the big coop outside) but it makes it tropical in the coop at 70 deg. I just got the cozy coop flat heater (especially for the winter) where it kicks on at 35 degrees on high setting. My coop is small at about 13 square feet. Am I being paranoid? Should I stop heating the coop all together until winter hits? Because the birds are fully feathered, shouldn't they be fine? Help!