Chapter 8 - Heating Needs

Heating requirements will vary with the type of broiler, stage of growth, broiler density, outside weather conditions, ventilation rates, and desired indoor temperatures. The preferred method of heating will depend on the percentage of building space being occupied by the broilers, energy costs, and stage of broiler growth. At times, more than one heating method will be used to economically provide the necessary supplemental heat throughout the growing cycle.

To determine heating needs, heat loss through ventilation air and building surfaces is compared to heat gain from bird heat dissipation. When heat loss is greater than the heat gain, supplemental heat is needed to maintain temperatures in the bird’s thermal comfort zone.

Building heat loss consists of heat transfer from the building interior to the outside through conduction, convection and radiation. Heat loss through the ventilation system typically demands the greatest share of fuel in cold weather. More than 50% of building heat loss is from ventilation air exchange. For each cubic foot of cold air brought into a building by fans or natural ventilation, a cubic foot of warm, moist air is exhausted. The cold air must be heated to maintain the desired temperature.

Typical sensible heat loss rates for poultry range from 0 to 17 BTU per hour per pound live weight with the lower values for warm air temperatures. Bird heat loss is also greatly affected by lighting, with heat loss rates being much greater when lights are on than when they are off.