Every year, as the weather turns cold, my husband starts closing down the windows of the chicken coop. He means well, but every year I explain why it’s very important to keep the chicken coop well ventilated, and why it’s even more important in cold weather (notice the windows are wide open – front and back).
Chickens generate a lot of moisture, ammonia, and heat – so it’s absolutely critical to ventilate well to remove the excess from the coop. The more time your chickens spend indoors, the more important it is to supply good ventilation.
Why Coops Need Ventilation
Chickens generate lots of water vapor, from both their breath and droppings, and all this water vapor tends to make coop air humid. High humidity (particularly in cold weather) makes chickens more susceptible to respiratory illness and frostbite. Good ventilation will remove this dampness and humidity from the coop, and chickens can withstand surprisingly cold temperatures without getting frostbite – if the air is dry.
Chicken also cause lots of ammonia fumes to be released into the coop from their droppings. Ammonia fumes can cause damage to the chicken’s respiratory tract at surprisingly low levels, and again, make the chickens more susceptible to respiratory illness. Basically, if you can smell ammonia near the coop floor, there’s enough to be harmful, so you need good ventilation to remove those ammonia fumes from the coop.
Good ventilation is also necessary to remove heat from the coop during warmer weather. Chickens do best in temperatures below 75°F and really start to suffer above 90°F, so ventilation is needed to keep the coop at least as cool as the outside air.
Good ventilation also supplies oxygen-laden fresh air that the chickens need, removes dust particles suspended in air from the coop (ever notice how dusty chickens are?), and dilutes any disease-causing organisms in the air.
When to Ventilate?
Chickens produce water vapor, ammonia, and heat continuously; so the chicken coop needs to be ventilated all the time – day and night, summer through winter. If a storm is causing torrents of rain, then it’s ok to shut down some of the ventilation for a little while – otherwise the coop should always be well ventilated.
In areas where very hot weather’s not a problem, one square foot of vent opening per ten square feet of floor space is generally advised. In hot weather areas, it’s often recommended that entire sides of the coop be constructed so that they can be removed (and replaced with hardwire) to maintain sufficient ventilation. If your climate is very wet or your coop is crowded, more than the recommended amount will also be needed. However the ventilation is supplied, make sure all openings are securely covered with something like hardware screen that predators can’t get through or get to your chickens through.
In cold weather, make sure that the ventilation isn’t causing drafts – any ventilation that will be used during cold weather should be high up and hopefully protected from rain and snow by roof overhangs. You don’t want a cold draft wafting across your chicken roost(s) at night. In warm weather, vents that provide a breeze for the chickens are good so openings lower in the coop are desirable.
Obviously, the amount and location of ventilation needed changes as weather conditions change, so it’s important to have many ventilation options that can be opened or closed as necessary. Consider your coop ventilation requirements carefully, and plan for more, not less. And, don’t shut off all the ventilation in winter – chickens need it then too!