More recently, tunnel ventilation has become popular as a means to alleviate heat stress
in very hot weather. By placing all fans at one end of the building and admitting fresh air
at the other end, relatively high air velocity provides additional cooling for broilers. For
totally enclosed buildings, tunnel ventilation presents a difficulty for the operator to
decide when to shut air inlets and open tunnel curtains at the end opposite the fans.
Some environment control systems are available to automate this feature.