Evaluation of heat stress using temperature-humidity index in laying hens in battery cages under Bursa conditions

Heat stress has become a more severe threat to the poultry industry with increasing global warming. Poultry is a sensitive animal affected more quickly by environmental conditions than other farm animals. Therefore, they are more easily exposed to heat stress. High temperature and relative humidity are significant environmental factors affecting animal growth, productivity, and welfare by causing heat stress. In laying hens under heat stress, egg production decreases, feed consumption increases, feed efficiency decreases, and deterioration in egg quality occurs. This study aims to determine the heat stress of laying hens using the temperature-humidity index (THI) in a farm where commercial egg production is conducted in battery cages in the Bursa region. According to the study results, the highest THI values occurred in the summer months and were at a critical level for chickens in July (26.0) and August (24.8). There is no statistically significant relationship between egg yields obtained in spring, summer, and autumn and the calculated temperature humidity index values. There is an inverse relationship between indoor temperature and egg production.