How long can the light be left on in the coop? Right now it is on for about 16 hours a day. Partially because it is in a dark area and to give a little heat. Next couple of days it will be about -30.
Chickens need dark just like humans do. But I can see what you are trying to accomplish especially with -30 temps. I am using two 75 watt black light bulbs in our coop right now. My husband gave me a double outlet photography light to use. The black light doesn't mess with their vision and internal clocks like regular, for want of a better word, light can. When the day temps get above freezing I only run it at night using a timer to turn it off and on. At the moment we are catering to a broody hen so we are trying to keep the temp up in the coop. It runs about 22 degrees overnight and 32 during the day. We are also having trouble with frost bite in spite of more than ample ventilation in the coop and regulating the temp seems to have helped.
