Poultry slaughtering and processing plants typically process 20,000 or more birds per day. The shackling, killing, scalding, and picking areas of the plant emit airborne microorganisms, moisture, and dust. These contaminants are unwanted in the processing and packing areas of the plant because they can affect product quality and safety. They also pose a potential threat to the health and well-being of the workers in the plant. This publication discusses the design and maintenance of the ventilation systems used in poultry processing plants.