Temperature, humidity, ventilation, and lighting together create the physical environment that determines much of the daily welfare experience of farmed pigs.
The physical environment of pig housing determines the baseline quality of life experienced by every pig in the unit continuously throughout their lives. Temperature outside the thermal comfort zone causes direct physiological stress — cold pigs shiver and pile, hot pigs show respiratory distress and reduce activity. High ammonia concentrations from inadequate ventilation cause chronic respiratory irritation and eye damage. Poor lighting prevents normal activity-rest cycles. Getting these environmental parameters right is a foundational welfare investment that benefits all aspects of pig health and behavior. Environmental management failures that are allowed to persist represent ongoing, preventable welfare harm affecting the entire population in the unit simultaneously.