Chicken coops are more high-tech than many people realize. A tunnel-ventilated coop is one type of housing used for chickens. It requires planning and equipment to build and maintain, since it essentially makes an indoor wind tunnel to keep the henhouse cool. Despite the possible expense, there are benefits to choosing this type of coop, especially in warm areas, since the inside air flow can be reduced enough to keep the chickens laying eggs throughout the winter months.
Overview: Tunnel Ventilation System
The tunnel ventilation system is created by putting fans at one end of the chicken coop. Air intake openings are at the opposite end, and the fans pull the air through the coop. This creates a wind tunnel that provides fresh air and a cooling breeze for the chickens. They may require additional cooling pads to supplement the fans, but the tunnel ventilation system will do most of the work to keep the chickens comfortable.
Pro: Cooling System
The major advantage to tunnel ventilation is cooling the chickens in hot weather. At least 50 percent of the fans should be running to cool the henhouse. For example, at least four fans should run if the coop has eight fans. In cooler weather, the fans can be slowed and some of them completely stopped so the coop stays warm but still ventilated to prevent foul air that causes respiratory problems in the birds. If it is warm enough, the chickens can continue to lay eggs all winter long, instead of slowing down or stopping egg production because of the cold.
Con: Equipment and Maintenance
Tunnel ventilation requires an airtight coop except for the intake vents and fans, and it must have the fans at one end to work. Without them, the coop can quickly get too hot and stuffy for the chickens. Spare parts such as fan belts should be kept accessible in case of equipment malfunction. Backup generators are important in case of power loss. The cost of these items, and the power required to run the fans, can add up for those watching their expenses.
Con: Crowding Chickens
The chickens will also gravitate toward the cooler end of the coop. In a tunnel-ventilated coop, this is the air intake end of the building. They can overcrowd each other in their effort to get to this cooler side of the house, which hurts egg production. Putting up additional fencing inside will separate them into smaller groups and keep the chickens from crowding each other. Preventing such chicken mobs keeps the birds healthier and happier.
Other Types of Ventilation
There are other types of ventilation out there for those concerned about the cost of tunnel ventilation. Smaller coops for backyard chickens may only need windows cut into the house. Place these at the top of the coop to let hot air rise and exit. A wind turbine is a wind-powered unit, often silver in color, that can be seen on the roof of many human homes. They are like a small wind mill; the wind blows and turn the blades of the turbine, which draws the hot air up and out of the coop. Both of these methods use far less materials and electricity than a tunnel-ventilated coop, but they rely on natural air currents to work and do not create their own cooling breeze.