Vents, cover or leave open?

[tbakko]

My coop has 4 vents, 2 on north and 2 on the south sides, the coop is pretty well protected from the wind on all sides except the west. The vents are each 7" x 9" and covered with metal screen. The wind direction in the winter is predominately from the west which is the end that the nesting box and plexiglass window are on. My question is, do I need to have covers on the vents for winter or just leave them open. Our winters here in Boise can get rather cold at times, like down into single digits but more commonly in the 20's.

 

[Alaskan]

I would maybe close the one windy side, if the wind then blows over the perches.

Otherwise, I wouldn't close them down.

 

[Bear Foot Farm]

That's enough ventilation for 3 birds.
If you have that many or more, leave them open except im bad storms

 

[Hokum Coco]

I am subject to arctic conditions here in Canada for days at a time during the winter months.
As a rule of thumb I keep my vents closed when the temperature is below freezing inside the coop and open when it is above freezing outside the coop.
Humidity and ammonia are your main concerns and if you find either in to high one must increase ventilation to combat..

Diary of last winter cold snap check out the link:

https://www.backyardchickens.com/t/738994/chickens-arctic-conditions-prolonged-period