we have been consistently cold, and what I am seeing is a loss of egg production, but my birds are getting used to it, they are outside strutting around in pretty darn cold weather. I don't add light or heat.
I caution you on a tightly closed coop, the moisture will build up fast, and that is where you will get frost bite. Instead of adding heat, add feed and make sure they go to bed with a full crop. A lamp, an extension cord, high wind and water and snow, are a darn good recipe for a fire if you ask me.
Mrs K
Mrs K, I know the standard is more ventilation, BUT...there are some of us, that in these frigid temps, real temp tonight of -10 and tomorrow -28 at night, with horribly high OUTSIDE humidity...I had issues when I opened up my coop more, in these kinds of temps, when I installed a DIY water heater and the OUTSIDE humidity flash froze on every surface of the coop.
Unfortunately, some of us are facing issues that are unusual, for most of the country. I ended up, closing most of my ventilation also. I left my highest vent open, and it does suck out "some" of the inside moisture...if I left my coop more open...I get 1/4th inch of frost on the walls in minutes...I am not heating their coop, and am seeing a bit of frostbite, only in these horrid temps...BUT, my cockerel, got a heavy dose of frostbite on his comb and wattles, when I had MORE ventilation open, than now that I have closed quite a bit of the coop up.
It's hard to adjust for and figure out the right amount of temps and ventilation and can be very dangerous for areas that face high outside humidity with the frigid temps. Someone near here, lost a whole flock...I don't know what there set up was, but all their birds froze. I Have been on the Alaskans thread and read tons of it, BUT, they have dry cold...where as here on the east coast, we have very WET cold....I have yet to get my ventilation right..or maybe I am fighting a battle that is out of my hands...I have tried both..more ventilation, less ventilation...so far, less has been better for the birds and I am getting less frostbite! I do leave the DIY water heater on though, even at night, but no heat lamp...wondering on tomorrow night though....the fires scare me also...I do give the birds a nice hot water breakfast of layer pellets and a few broken up eggs, shell and all, early in the AM( bout 7 amish )water warm and about an hour before sunset, I give them some pretty warm water too...that seems to be helping them also. The warm AM food seems to help them maintain their body temps through out the day...it's the frigid nights I worry about.
I am seriously thinking of trying a heat lamp, for Friday night, with real temps at -28, and wind chills??? and the 100% humidity...I still don't have it all figured out, but wanted to add my two cents for those who are in my predicament and facing that darn outside, high humidity...I guess what I am saying, is, try out some different ventilation, more. less, heat, no heat, for YOUR area, check the humidity and your coop walls and the birds combs and wattles...it might be, that you are in an area that the outside humidity is more than what will be in your coop and the "standard" answer just isn't going to work for you...again, it only took a minute or two, for my coop walls to flash freeze, when I opened up the coop as much as I could. Just food for thought!
One more quick idea I had the other day. I am considering using a small computer type fan, to help the inside moisture, to the outside...the big commercial operations use huge fans in those big buildings...like an exhaust fan...only much smaller...like I said, I am still trying to figure this out myself, in my own weather conditions!
Stay warm everyone..this is gonna be a VERY LONGGGGG winter! Best to all of you and your flocks!