How much ventilation does a quail hutch need?

[dand883]

I'm in the process of building a new quail hutch and I'm weighing the need for ventilation vs being sealed up to block out drafts for the winter. I'm in Canada, so I'm worried about the cold temps we get.
The hutch itself is approx 3'x6'. One side is going to 1/2" hardware cloth on the bottom, the other I am going to fully close the bottom with plywood and have it be a permanent sand box.
My plans are to totally enclose the two sides and the back. The front is pretty well a full door panel on either side. One I plan to have hardware cloth over it and the sandbox side have a piece of plexiglass to let in some light. The doors don't seal tightly by any means, so there will be sole air flow around it, but not enough for there to be a draft blowing through on them.
In between the two sides is plywood with a door cut out for them to go back and forth.
My thinking is the sandbox side should be as closed on as possible to keep them warm over the winter and the open side let's the poop fall through and gets them some air and sun.
Will the air leaking around the door and the doorway cut through the plywood center divider be enough ventilation for them, or should I drill some holes along the roofline to vent it? I see all kinds of suggestions for ventilation for chickens, but not so much for quail.

 

[Cazook]

More ventilation is better, iirc quail poo has even higher levels of ammonia than chickens, and being quail it can gather up quickly and pose health hazard, nevermind the moisture that will make them miserable. I put a bundle of straw on a seedling tray in my quail cage for them to nest. If it gets cold they will bundle together but often they will ignore it and just sleep in random spots throughout the cage. My cage walls are half hardware cloth, half planks with 1cm spacing between, so... lots of ventilation. They don't seem to mind the cold as much as you would think for their size, especially if they can bundle together.