Ventilation and Environmental Monitoring of Broiler Houses in California

Abstract

The ventilation and environmental control parameters of two broiler barns in California were measured and monitored as part of the National Air Emission Monitoring Study. This paper presents the ventilation measurement results from September 22 of 2007 to March 31 of 2009, which covers ten broiler production cycles. The duration of each cycle was about 45 d for raising the new chicks to 2.3-kg adults. The two broiler barns had identical structural design and ventilation, feeding and litter management practices. Each barn contained about 21,000 broilers in each production cycle and was mechanically ventilated with 11 fans, including one 91-cm fan and ten 122-cm fans. All the fans, heaters and evaporative cooling systems were automatically operated to control the house temperature from 32C at the beginning to 20C at the end of each production cycle. The environmental parameters that were monitored included temperature, relative humidity and static pressure inside the houses, and ambient temperature, relative humidity, wind speed and direction, and solar radiation outside the houses. The operational status and rotational speed of all ventilation fans were continuously monitored. The ventilation rate of each house was estimated by calculating the airflow rate through all the fans based on the depression of static pressure in the building, fan performance and operation status. The production cycle average daily mean ventilation rate was correlated with cycle average daily mean ambient temperature. The ventilation rate for any day within a cycle was influenced primarily by bird age and ambient temperature. The daily ventilation rate of a barn ranged from 0 to 75.8 m3/s with an average of 13 m3/s. The minimum and maximum ventilation rates occurred in January and July/August, respectively. Average ventilation volume per broiler during a growth cycle was 2341 m3, and ranged from 1161 to 5214 m3.