Why does a failure in the static pressure of a tunnel-ventilated shed cause dead air zones and localized heat stress?

Tunnel ventilation relies on a sealed environment and controlled static pressure (the difference between inside and outside air pressure). When exhaust fans pull air out of a sealed shed, it creates a partial vacuum. If the static pressure is maintained at the correct range (usually 20 to 30 Pascals), incoming air is forced through the cooling pads at high velocity, mixing thoroughly with the house air and creating a uniform wind-chill effect. If there are air leaks (in the ceiling, side doors, or damaged curtains), the static pressure drops below 10 Pa. Consequently, the incoming air moves sluggishly and falls directly to the floor at the inlet end, failing to reach the birds in the center and fan ends. This creates hot, humid "dead air zones" where temperatures rise rapidly, triggering heat-stress-induced mortality and pale, thin-shelled eggs. Farmers can study ventilation engineering in the Poultry Encyclopedia, buy high-precision static pressure sensors on Poultry Plaza, check daily rate margins on Poultry Rates, and trade on Murghi Mandi.