Broiler House Ventilation: The Heat-Removal Bound, Maximum Stocking Density, and the Ambient Region Where No Ventilation Rate Prevents Heat Stress

Tunnel ventilation can remove only the sensible heat that moving air can carry, and evaporative pads can cool incoming air only toward its wet-bulb temperature, at the cost of raising its humidity. This paper models both limits from stated assumptions for a finishing broiler flock. Total metabolic heat is taken as 8.0 x m^0.75 watts per bird (m in kilograms), so a 2.5 kg finisher produces 15.91 W in total, or 6.36 W/kg, of which 2.86 W/kg is sensible at a house temperature of 30 degC. Holding the house within 2.0 K of the inlet temperature then requires 4.46 m3/h of airflow per kilogram of live weight for the birds alone, and 5.5 m3/h/kg is the recommended design value at an ambient temperature of 30 degC and 50% relative humidity with pads. For an example house of 1440 m2 stocked at 30 kg/m2 (17,280 birds at 2.5 kg, 43,200 kg live weight), the total metabolic heat is 274.8 kW, the required airflow including an envelope allowance is 201,595 m3/h, and an installed maximum of 291,600 m3/h gives 1.45x headroom. The binding limit is usually not the fans. With pads at 75% efficiency, the highest ambient temperature that can still deliver inlet air at 28.00 degC falls from 38.24 degC at 30% relative humidity to 34.22 degC at 50%, 31.37 degC at 70%, and 29.02 degC at 90%. Above the absolute limit, where pad outlet air itself exceeds 30.00 degC (36.46 degC ambient at 50% humidity, 33.48 degC at 70%, and 31.05 degC at 90%), no ventilation rate at any stocking density can hold the house at or below 30 degC. In that region the only options within ventilation are to not stock finishers in that window, to shift the finishing phase out of that window, or to use refrigerative cooling, which is outside this model. All results are SIMULATED, NOT MEASURED; nothing was built or tested on birds. AI disclosure: This paper was drafted and computed with the assistance of Dave, an artificial intelligence system. The author reviewed the assumptions, the model, and the results, and takes responsibility for the contents.