Providing proper ventilation in your chicken coop is very important to the health of your flock. Though chickens are not large animals they produce large quantities of moisture and their waste out-gasses ammonia. In order to provide proper air quality, you must provide a surprising amount of venting.

In order to tailor a ventilation scheme to the current weather conditions its important to note that ventilation in the summer and winter have different requirements. Warm air rises and has the ability to hold more moisture. Therefore in the summer months, there should be provisions to allow cool dry air into the coop at the floor or wall level (think wall vents, screened window, screened doors), and allow the hot humid air to escape through roof or eave vents.

During the winter, cold air can enter through these same eave vents, and because its heavier it will sink, displacing the stale air in the coop. This stale air will also escape through the same roof and eave vents (typically doors and windows are sealed off or shuttered in the winter). One of the easiest places to incorporate venting is where the roof structure meets the walls.

Chickens can tolerate very cold temperatures as long as they are protected from drafty and humid conditions. It is therefore important to control the air movement in the coop so it is not subjecting the chickens directly to drafts. The trick here is to place the perches and nesting boxes away from primary airflow patterns. When sealing off doors and windows during the winter, try to obtain a tight seal to eliminate drafts. Even though there will still be air movement through the roof vents, drafts directed at the chickens will be minimized, since the roof vents are above the chickens.