PRECISION BROODING OF BROILER CHICKS: A REVIEW OF THERMAL PHYSIOLOGY, SENSING, AND A FRAMEWORK FOR EMBEDDED CONTROL

In broiler pens, temperature, humidity and air quality are all controlled by a single factor: ventilation. Yet much of the control research has focused on temperature alone. This review treats the first four weeks of broiler production as an engineering problem. It translates experimental evidence on chick responses into measurable design specifications and derives the heat, moisture and gas balances that limit what a ventilation system can achieve. It then reviews the sensing, embedded, communication and control technologies reported for poultry houses. Finally, it proposes a layered reference architecture, a constrained control formulation and a minimum set of metrics for validation studies to report. A psychrometric analysis shows that ventilation removes moisture only when the outdoor air has a lower humidity ratio than the target indoor air. For example, with a set point of 29.4 °C and 65% relative humidity (RH), outdoor air at 27 °C and 80% RH holds 1.2 g more water per kilogram of dry air than the target indoor air. In such warm, humid weather, ventilation cannot dry the litter. Studies of low-cost ammonia, particulate matter and humidity sensors report cross-sensitivity, drift and limited field validation. Most low-cost Internet of Things (IoT) nodes have been checked against reference instruments, but not against chick outcomes. Control studies for broiler houses are mostly simulations or single-site pilots. The review identifies research gaps and priorities. The proposed framework is conceptual and has not yet been tested experimentally.