The Effects of Simulated Transportation on White-Feathered End-of-Cycle Laying Hens

Abstract

This study evaluated the impact of five temperature (T)/RH, three durations, and two levels of feather cover (FC) on the welfare of white-feathered end-of-cycle hens (65-70wk). The factorial arrangement with T/RH (-10°C uncontrolled RH (-10), 21°C with 30 (21/30) or 80% RH (21/80), 30°C with 30 (30/30) or 80% RH (30/80)), duration (4, 8, 12h), and FC (105 well-feathered (WF), 105 poorly-feathered (PF)), included 210 hens/replicate/farm (three total) during simulated transport. Crates (one/duration/replicate), divided in half for each FC (seven hens/side), were placed in a climate-controlled chamber. Pre-exposure all hens were fasted (6h). Pre- and post-exposure, hens were weighed (live shrink calculated) and five hens/treatment had core body temperature (CBT) recorded and blood samples taken (delta (∆) blood physiology values calculated). Behaviour was analyzed using 5min scan sampling. Post-slaughter, muscle characteristics were analyzed. A randomized complete block design using ANOVA was used for analyses (PROC MIXED, SAS 9.4; blocked by farm; significance at P≤0.05). Mortality was highest for PF hens at -10. Hen ∆CBT were greater (positive) at 12h for all T/RH than at 4h for 21/30, 21/80, and -10 (negative). Hen ∆glucose were greater (negative) at 4 and 12h for -10 than 4h at 21/30, and all durations for 21/80, 30/30, and 30/80. Hen ∆sodium, ∆hemoglobin, and ∆hematocrit were greater (positive) for -10 PF than WF (negative). Hens spent more time shivering and motionless in -10, while hens panted frequently in 30/80 for both FC and in 30/30 for WF hens. Live shrink increased with increasing duration. Muscle pH measures (except initial pH) were higher in hens exposed to -10 and this difference was exacerbated by increased D (final breast and thigh pH). For muscle colour, breast and thigh (both FC) lightness values were lowest in the -10 treatment. Breast and thigh redness values were higher in hens exposed to -10. Thaw and cooking losses were impacted by T/RH and duration, with cook loss also influenced by FC. Overall, the largest impact was found in hens exposed to -10 for increasing D compared to other treatments, demonstrating stress responses and reduced welfare for behaviour, blood and muscle physiology.