My major advice would be that it is far better to have more ventilation available than you end up using, than to end up needing more than you have (hacking holes in the coop at -20 F is just no fun at all).
Humidity (which is what happens with insufficient ventilation - chickens put out *vast* amounts of water vapor, one way and another) will give you frostbite at quite mild temperatures, so it is generally a good idea to sacrifice some warmth for the sake of *dryth*. Where you live, I assume you will need some supplemental electric heat anyhow; but the drier the coop air, the less heat it takes to keep frostbite away. There may be some times you end up shutting down all the vents, but if you do, it needs to be done in full awareness of the tradeoff you're making between drier cold and more-humid less-cold.
In pursuit of dry air you will also want to a) stop up all small air leaks, as they become condensation(frost) farms that make it hard to keep humidity down; and b) think about puttng plastic or bubblewrap over the windows to reduce frost there.
Good luck, have fun,
Pat
Humidity (which is what happens with insufficient ventilation - chickens put out *vast* amounts of water vapor, one way and another) will give you frostbite at quite mild temperatures, so it is generally a good idea to sacrifice some warmth for the sake of *dryth*. Where you live, I assume you will need some supplemental electric heat anyhow; but the drier the coop air, the less heat it takes to keep frostbite away. There may be some times you end up shutting down all the vents, but if you do, it needs to be done in full awareness of the tradeoff you're making between drier cold and more-humid less-cold.
In pursuit of dry air you will also want to a) stop up all small air leaks, as they become condensation(frost) farms that make it hard to keep humidity down; and b) think about puttng plastic or bubblewrap over the windows to reduce frost there.
Good luck, have fun,
Pat
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