Abstract
Transportation of poultry is stressful. The transportation of broilers has been well studied, while the transportation of layer pullets from rearing to laying facilities has not been thoroughly evaluated. This experiment aimed to establish the effects of temperature (T)/RH combinations and duration (D) of transport, via a 5 × 2 factorial arrangement of simulated transport conditions using 5 T/RH combinations (21°C with 30% RH [21/30], 21°C with 80% RH [21/80], 30°C with 30% RH [30/30], 30°C with 80% RH [30/80], and -15°C with uncontrolled RH [-15]), and 2 exposure D (4 or 8 h). Pullets (18-19 wk; n = 240) were obtained from 3 commercial farms (N = 3 farms). Pretreatment, birds were orally administered a miniature data logger to record core body temperature (CBT), an initial blood sample was taken (5 birds/replicate), and initial foot T was recorded. Behavior during exposure was video recorded. Following exposure, a final blood sample was taken (analyzed for heterophil to lymphocyte ratio, partial pressure of CO(2), total CO(2), bicarbonate, and glucose), birds were slaughtered, and data loggers were retrieved. Data were analyzed as a randomized complete block design via Proc Mixed (SAS 9.4) and significance was declared at P ≤ 0.05. There were no interactions observed for the T/RH and D combinations throughout the study. The CBT and foot T were lowest in pullets exposed to -15 compared with all other treatments. Foot T was also highest in pullets exposed to 30/80 compared with -15, 21/30, and 21/80. There was no impact of T/RH on pullet blood physiology. Activity and thermoregulatory behaviors were impacted by the T/RH combinations. Pullets exposed to 30/30 and 30/80 spent the most time panting. Pullets exposed to 30/80 also spent the least amount of time motionless. Duration had minor impacts on pullet CBT, blood physiology, and behavior. These data indicate that as a response to thermal stress, layer pullets were successful at implementing mechanisms to maintain homeostasis.