They should be fine I have a turkey that is molting she is even fine she just stays in the chicken coop right now by her own choice. Its warmer more bodies my turkey pen is only 3 sided and there fine also
I live in central IL we will be around -5 in a few nights. All I use is a light to substitute for the sun it goes off aroind 10 or so and dont come back on till 5am. The have been fine so far and we have been at 7 deg a few morn now. Remember sun up is usually the coldest point in the day