Space and ventilation questions?

[Chickie friend]

I have an old play house that was converted to a coop. Its 17² ft (how do you get 17² feet you ask? by having a tree go though the middle of course) currently there are 4 chickens in there. There are 3 windows that provide 8 feet of ventilation, but only during the day.
Is that enough? My dad doesn't want to put more in because our cockeral starts to crow at 6 and he wants sleep. We could easily attach hardware cloth to one window and keep it open at night.
Could, should I add 2-3 more chickens* (if they were bantams)? I have a broody now too who's sitting on some golf balls and I don't know if I should try to break her.
*Chicken math is very, very hard to resist

 

[Chickie friend]

Ok, forgot to mention that I have three other silkies in a different coop and the broody (dusty) usually sleeps there. All the chickens in the converted playhouse coop are large fowl. (They are pretty young still though. they will be 5 months old in January) dusty is older, that would be really wired if she was broody now

 

[3KillerBs]

If you close up all the ventilation at night the number of chickens you can safely keep in there for the long-term is ZERO.

Adequate ventilation, 24/7/365, is the #1 thing required to keep your chickens healthy.

The usual rule for standard-sized chickens is 4 square feet of floor space in the coop, 10 square feet in the run, and 1 square foot of that 24/7/365 ventilation PER BIRD.

So the number of chickens in 17 square feet is 4.25. You're good with your current flock of 4, but would be courting trouble to add more because over-crowded chickens frequently develop health and behavioral problems.