I've always admired your coop and have followed that design for a while. I have 3 coops and another complex of 5 breeder units. Most have huge openings but I have a question for you.Do your birds(And your electric bill) a favor, and get rid of those heatlamps. Chickens can handle cold weather. With their feathers, they are perfectly insulated and capable of dealing with what you call cold. And open the vents up. Lack of proper ventilation, is a much bigger problem in the winter, than the cold. You may even have to open one, maybe both, of those windows.
Chickens generate a lot of humidity, just from breathing. And we are not even talking about moisture, and ammonia from their waste. If that moisture is not removed with proper ventilation, the birds can suffer from frostbite, and can even be subject to various respiratory problems. Heatlamps can also prevent your birds from properly acclimatizing to the winter cold. Then, if for some reason, the heat goes away, from either a power loss, or bulb burnout, then your birds WILL suffer. And really all for nothing. Another thing heatlamps are good for is burning coops down. Every winter, we will read again, about somebody burning their coop down, because they were worried that their birds were chilly.
Check out the coop below. It is a proven 100yr old design, that is unheated, and uninsulated. And the whole front wall is open. This is the 5th winter, and I've never lost a chicken to the cold, and none of them has ever suffered from frostbite. Coops like this were in use all the way up into Canada, in -40 temps.
I have a building that slopes so the low side is on the north. I built it that way so sunlight can reach the berry patches on the north. I need to rebuild that building. I can't go as tall as yours because of the berries. Do you think, given your experience with that design, that the lower level can be dropped a foot or two and the tall part can be lowered 3 or 4 feet and still function the same?
-20, no sweat. some people report no problems to -40. It was -19 here last winter and my buildings large openings let the breeze blow right through.Thank you, thank you! So what kind of temps can I expect these girls to endure? I guess I have far under estimated them. Is there a temperature I should try to be sure to stay above inside the coop? And what about a heat lamp just for night? (Makes a good night light for them)
I'm not an adherent of the 'no drafts' philosophy as long as the birds are dry. They can live in trees and I don't know how one keeps a breeze out of a tree.
Just at night would make matters worse.
You don't want/need a "night light" - chickens need those hours of darkness and do not need heat at night any more than they do during the day. I have kept chickens in unwired (thus unheated) coops in temperatures below zero and never had an issue.
X2