Broilers' head behavior as an early warning index of production and lung health under ammonia exposure

This study investigated the effects of ammonia exposure (0, 15, 25, and 35 ppm) on head behavior, production performance and lung tissue morphology of broilers, and the relationship between head behavior, production performance, and lung tissue injury. In this experiment, a total of 264 AA commercial male broilers (21 d old) were assigned to 4 treatment groups with 6 replicates of 11 chickens for a 21-day trial period, the frequency of head-scratching and head-shaking behavior at the initial stage (2, 24, and 72 h) of ammonia exposure were recorded, and the production performance indices and the lung pathological changes after 21 d of ammonia exposure were observed. The correlation analysis was established between head behavior and production performance indices. Results showed that head-scratching behavior increased under 15 ppm ammonia for 72 h, head-shaking behavior increased when exposure to 15 ppm ammonia for 2, 24, and 72 h, and lung tissue was injured when exposure to 15 ppm ammonia for 21 d. However, exposure to 15 ppm ammonia did not influence growth performance. Compared with the control group, exposure to 25 ppm decreased the ADG and exposure to 35 ppm decreased the ADG, ADFI, and F/G. Furthermore, the increase in head-shaking frequency after 2 h and 24 h ammonia exposure was significantly associated with production performance and lung tissue injury after 21 d ammonia exposure. In conclusion, the head-shaking behavior at the initial stage of ammonia exposure can reflect the degree of harm of the later production performance and lung tissue health.