It really depends on the coop; with this coop, it appears that a few inchest at the top of the front and a side would provide for the air to circulate. Or, a few inches on opposing walls.
The best scenario is to draw some air in, allow it to circulate, and then push it back out. If it's circulating, it'll flow throughout the coop.
You really need to be diligent about changing the bedding often. If you keep the bedding very dry, and have decent ventilation, you shouldn't have a bacteria issue.
You're completely correct, Poulets - most of the moisture and bacteria are found at ground level in the bedding.
The best scenario is to draw some air in, allow it to circulate, and then push it back out. If it's circulating, it'll flow throughout the coop.
You really need to be diligent about changing the bedding often. If you keep the bedding very dry, and have decent ventilation, you shouldn't have a bacteria issue.
You're completely correct, Poulets - most of the moisture and bacteria are found at ground level in the bedding.