24. The design of ventilation systems has a major influence on bird welfare. Ventilation systems are designed to provide air containing sufficient oxygen for the normal growth and development of the turkeys and to remove excess ammonia, carbon dioxide, moisture, dust and heat. In conventional (enclosed) houses with controlled environments the ventilation system should be sufficiently flexible to cope with the changing needs of the stock. In cold weather the ventilation system must deliver air to the birds without allowing them to become chilled. In hot weather the system must have sufficient capacity to prevent the temperature in the building rising to excessive levels. The efficiency of the ventilation system also has an important influence on litter condition.
25. In hot weather, a fast airspeed at bird level can be used to moderate the effects of high temperature. Additional air movement can be provided by using recirculation fans to blow air around the house at bird level. This strategy is especially important in naturally ventilated houses but is worth considering for all turkey buildings.