It saves on electricity used by fans. Natural ventilation may not be appropriate in the colder areas of Australia where a suitable climate occurs only for a few days or two to three weeks a year. In this case power ventilation is the best option. If the natural ventilation system is not included then the shed is ventilated during the period between the use of minimum and tunnel ventilation by using up to half the tunnel ventilation fans or a combination of special minimum ventilation fans and up to half of the tunnel fans in conjunction with the minimum ventilation inlets or the tunnel inlets. The number of fans operating depends on the outside temperature, density of chickens and target temperature.
Ventilation rate is varied in response to shed temperature.
The choice of system is related to cost and effectiveness. A good cool pad system costs more, reduces temperature more and gives drier litter than the other systems. Proceedings 1992 Poultry Information Exchange, Surfers Paradise, Qld, Australia. Further information For further information contact Geof Runge. The State of Queensland, Department of Primary Industries 1998.