| dc.description.abstract | Ammonia is a common airborne contaminant in poultry housing, originating from the microbial
breakdown of bird excreta, and is known to adversely affect bird health and behaviour. Despite the use
of ventilation and management practices to control its levels, concentrations frequently exceed
recommended thresholds. While the effects of ammonia are well-documented in broilers and laying
hens, empirical data on turkeys remain limited. Turkeys experience prolonged exposure due to longer
rearing periods and may exhibit different behavioural sensitivities.
This study investigated short-term behavioural effects of ammonia at 0 (fresh air), 25, and 45 ppm
from both natural (excreta-derived) and artificial (cylinder) sources on Hybrid XL turkeys. Twenty
female turkeys were repeatedly tested in a two-chamber apparatus and video recorded. Behavioural
data including latencies to enter (LTE) and forage (LTF), foraging, avoidance, and vocalisations were
analysed. Survival analysis accounted for censored latency data, modelling individual and session
effects as random intercepts. Cox mixed-effects models were used to estimate hazard ratios (HR).
Latency to forage and enter were significantly reduced at 25 ppm natural ammonia compared to fresh
air (HR_LTF = 1.89; HR_LTE = 2.16), indicating faster engagement. Latency to forage was also reduced
at 45 ppm natural ammonia (HR = 1.74). No significant differences were observed between ammonia
sources in latency or behaviours. Foraging frequency and duration were unaffected. Aversive
behaviours showed no significant treatment effects, though vocalisation frequency decreased by
45.3% at 45 ppm artificial ammonia compared to fresh air.
Results suggest turkeys may exhibit limited overt behavioural aversion to ammonia at tested
concentrations. Behavioural indicators alone may underestimate welfare impacts. Future research
should integrate behavioural, physiological, and health metrics over longer periods to inform air
quality standards tailored to turkeys. | |
