Poultry house control systems in the U.S. typically consist of single or multiple stage
thermostats which control ventilation rate by regulating the position of curtains or
damper inlets along the side of the house and/or the number of fans being operated.
For hot weather, a separate thermostat or one of the upper stages of a multiple-stage
thermostat may be used to control evaporative coolers – usually by turning water supply
valves or pumps on or off. Lights are typically controlled by electromechanical timers.
Other variables like humidity, static pressure and ammonia are not usually controlled.
Monitoring is usually restricted to house temperature using glass or dial thermometers
hanging in the house in the exhaust air stream. Light levels may be spot checked with
hand-held meters. Humidity and ammonia are usually not measured, but producers
usually try to make adjustments in ventilation rates or set points based on perceived
humidity levels or ammonia levels in the poultry house. Alarms are usually limited to
audible devices which can be heard at nearby farm offices or homes, and which can be
triggered by power failures (which would result in a loss of ventilation in the event of
powered ventilation systems), high temperatures, or failure of the watering system.
Some alarm systems use regular wired or cellular telephones with automated dial out
triggered by out-of-range variables to deliver trouble messages stored on tape or in
solid-state memory