My wife thinks I have to much ventlation and it wont protect the chickens during the winter (We are in Milwaukee, Wisconsin),
She reads her her forums that they need protection from the wind. That she thinks in a heavy winter storm, that it wont protect them.
Poor ventilation will kill chickens faster than the cold.
That said, cold also kills chickens.
I like to give my chickens choices. A sheltered spot out of the wind with low moisture from outside and a wide open space. Then it's their fault if they choose what we think is the wrong one, not the fault of the builder.
If I remember correctly our chicken house had all four sides enclosed with the ventilation at the top by the roof.
Something similar to what is seen on the left-hand side of your coop.
Invasive plants are Earth's way of insisting we notice her medicines. Stephen Herrod Buhner
Everyone learns what works by learning what doesn't work. Stephen Herrod Buhner
how many birds? i’d tend to agree with your wife, in a windy winter storm, depending on wind direction, there may not be anywhere for them to get out of the way of wind and blown snow. even if they had a corner to huddle in that wasn’t screen, could help a lot. wouldn’t have to take much more wood.
in general, lots of ventilation is good, but a little windbreak is good too.
We're in the middle of Missouri, and our coop is fully enclosed, with windows in the top 1/3, on two sides. I, personally wouldn't do less, and when I was in MI, that one was also enclosed on all 4 sides, with ventilation only at the top.
"The only thing...more expensive than education is ignorance."~Ben Franklin
"We can easily forgive a child who is afraid of the dark; the real tragedy of life is when men are afraid of the light." ~ Plato
My main ventilation comes from the top of the coop so that there can be air movement without it being across the chickens when they sit on their perches.
You need a lot of ventilation but it needs to be of the right kind and location.
Here are a couple of past threads you might find useful. They each link to different online copies of Fresh-Air Poultry Houses by Prince T. Woods (and which I bought a paper copy on Amazon).