A Continuous-Choice Assessment of the Domestic Fowl's Aversion to Concurrent Transport Stressors

Abstract

AbstractCharacterisation of the effect of transport on the welfare of fowl requires common currency methods that can compare the effects of diverse stressors using the same unit of measure. Aversion of broiler chickens (42 ± 1 days old) to vibrational and thermal stressors was investigated in a continuous free-choice procedure. Each choice-chamber had four compartments, connected via a central zone, offering a thermal stressor (T: 40°C, relative humidity 21%), a vibrational stressor (V: 2 Hz, 1 ms−2), concurrent vibrational and thermal stressors (VT), or no applied stressors (N). In experiment 1, there were no significant effects of stressor on the latency to leave the compartments after initial introduction (n = 24). In experiment 2, 12 subjects were introduced individually to a chamber for 4 h during each of a control and two treatment sessions. The results indicated that chickens did not avoid vibration, but significantly avoided the thermal stressor overall (T and VT; P < 0.001). As no interactive effect of the stressors was observed, all avoidance of the combined stressors can be attributed to the effects of the thermal stressor alone. Further work is required to establish ways in which delayed stressors can be studied using behavioural methods before common currency methods can be practicable.