I don't live far enough north to worry about it, but I'm wondering about how folks living in the northern latitudes deal with the reduced levels of lighting in the winter. Not talking about hours of light they say you need to keep them laying, I'm talking about surviving at all. In Mid MO, we are down to about 9 1/2 hours of daylight, so birds head for and are on the roost the rest of the time, or about 15 hours of each day.......which happens to be our coldest time of the year. We can get temps down to -5 or -10. Farther north, I would think that gets down to 6 to 8 hours of daylight / 16 to 18 hours of darkness and temps in the -20 or more range. Again, when it's not light out, my assumption is they are on the roost. They may not be asleep, but are huddled on the roost. No water, no food for 16 to 18 hours in sub freezing temps. Taken to the extreme up near the arctic circle, they may not get much natural light at all. Is there a point where you folks up north add and hour or two of light to allow them to activate to eat and drink? Again, not to stimulate winter laying, but simply to survive? Or put another way, how far north can birds survive without supplemental lighting? They can't migrate, so are stuck where we put em.