Evaluating ventilation?

[NancyNurseCxMama]

I have read articles that recommend one square foot of ventilation for each bird in the coop. No drafts but good air exchange.
Last night we were in the low thirties and very windy. I closed the two windows and the back vent in the coop. The remaining ventilation consisted of ten 2" holes that we drilled in the gable walls of the coop, near the roof peak, and whatever is provided by any air leakage in the coop itself. We have foil-backed insulation but only on the roof.
That "one square foot of ventilation for each bird" ain't gonna happen. In the summer, maybe, but not now. There is no way I could provide a draft-free six square feet of ventilation in that coop.
This morning, the outside temp was 32 degrees with humidity of 85%. I have a wireless temp and humidity monitor in the coop and it read 35 degrees with humidity of 84%. When I let the girls out today I checked the glass on the coop windows---dry, no condensation.
I am thinking we are doing okay but is there anything else I should be doing to make sure they're alright this winter?
I was worried about the cold and wind last night so I went out there late with a flashlight and peeked into the coop through the windows.
They were lined up on the top roost, sound asleep, all fluffed up, and looked totally comfortable. They looked like a TSC ad.
This is our first winter with chickens---TIA for any thoughts/advice!

 

[IslaBean]

I am in the same boat. This is also my first winter with chickens. I have closed both the windows in my coop too. Right now the only ventilation I have is the small opening going into their run and a couple holes in the top. I do leave the door open all day while they are free ranging so it gets lots of ventilation then. I'm not quite sure what I'm doing this winter.

 

[ChickenCanoe]

If it were me, I'd open those windows back up. I don't buy into the 'no drafts' concept unless the chickens are wet. They are outdoor animals. Chickens can live in a tree and there's no way to keep drafts out of a tree.
I have huge windows on both east and west walls of coops with the wind blowing right through and no problems for years. It can get down to -20F here with high humidity.
Chickens go to bed wearing down jackets and they can tuck their heads under their wings.
Of importance is making sure the roosts are wide enough so they can cover their toes with their feathers.

 

[Folly's place]

You can leave large openings on one side of the coop, the side away from prevailing winds. Openings above roost height are best. Two inch holes hardly count as ventilation! Open the area more and add more hardware cloth.
Post pictures!!! Mary

 

[NancyNurseCxMama]

You can leave large openings on one side of the coop, the side away from prevailing winds. Openings above roost height are best. Two inch holes hardly count as ventilation! Open the area more and add more hardware cloth.
Post pictures!!! Mary

I was under the impression that appropriate ventilation was judged by the humidity levels in the coop and that humidity was the big enemy.
I do open the windows, vent, and pop door during the day to air everything out. I also clean the PDZ poop trays at least every other day. No ammonia smells and no condensation or wetness that I can detect.
Any openings I add will be lower than the roosts. There simply isn't a heckuva lot of room for more holes in my coop. The six-foot-long vent is directly behind the roosts, the windows are across from the roosts. The nesting boxes are below the windows.
@Folly's place --- Perhaps leaving the windows open and adding some kind of baffle to the window openings to prevent drafts? Unfortunately the windows are directly in the path of prevailing winds.

 

[B Redhawk]

First off, there are coop designs that have a completely open side (usually the south side) with only screening (1/2 or 1/4 inch mesh (hardware cloth)), these were very popular in the 1910's thru the 1940's and they work very well.

I've seen the 1 sq. ft. ventilation per bird figures and for most people this just isn't possible. A better method is to calculate the sq. ft. of the floor then divide that by four to arrive at a minimum ventilation area. (example: 4x8=32 divide by 4=8 sq. ft. of vent space) In some parts of the US you will need more vent space, depending on winds.
The biggest thing is to have enough air exchange for when the birds are shut in for the night. Think of it from the view point of how much "stuffiness" you can sleep in. Then calculate the vent area so you would be comfortable sleeping in the coop.

I have a 4' x 8' coop (7' to 7'6" wall height) that has 5 sq. ft. of vent on the south face, 7 sq. ft. of vent on both the east and west wall (at the roof overhang line) and two openable windows of 4 sq. ft. each on the east and west wall about 1.5 feet below the bottom of the roof line vents.
There is space for 8 hens and their rooster and no problems with air quality because we are on top of a mountain and there is almost always a breeze of at least 2 mph. coming from the south. Our other coop is 8'x8' with 7'6" walls, it has south and north facing vents that are each 8 sq. ft. in the eve area and two 4 sq. ft. each windows on the east and west sides located 1.5' from the eves. I am going to add two more windows at the same height on the north and south walls because this coop can get a bit stuffy, it currently doesn't have any chickens living in it because of this lack of proper ventilation.

 

[NancyNurseCxMama]

This idea looks interesting but I am not paying for it. I can fashion something like that myself, I think---doesn't have to be plastic, lightweight plywood would do.
I have two double-hung windows in the coop and I might try this so I can leave the windows open but cut down on direct drafts.
You guys have me thinking here!
https://www.invisibleawning.com/pages/house-window-rain-guard-images

 

[aart]

Best way to evaluate if 'drafts' are too strong(literally feather ruffling) is to go out into coop wind wind is a howling.
There are many ways to damper the air flow.

 

[TJE]

My vents go all the way across the top of my coop. We get howling winds and -20 at times, so I will be adding a guard on the overhang that will hang in front of the vents to block draft. The guard will be several inches in front of the vents to all air flow. I don't have enough vents so I will be replacing my windows with hardware cloth and and installing with a shutter that opens from the bottom (kind of like a pop door) and place a bracket where I can prop the shutter open enough to allow air but blocking the wind. You could potentially cut out the whole area where you have holes, install hardware cloth to protect and add a shutter to prop open.

 

[NancyNurseCxMama]

Okay, I left the windows open last night and they lived to cluck about it. I shut the vent behind them, though.
FOFU has me being too cautious, I suppose. Newbie jitters.
Cold tonight but no winds so I will do it again.