Location: Livestock Behavior Research2013 Annual Report
1a. Objectives (from AD-416):
The objectives are: 1) to examine the cellular and molecular mechanisms of pain in chickens following beak trimming; 2) to identify if infrared beak trimming is a less painful method than hot blade beak trimming; and 3) to develop pain biomarkers for evaluating husbandry practices used in the farm animal industry.
1b. Approach (from AD-416):
A total of 1,056, 1-day-old, chicks (Hy-line, W-36) will be randomly distributed among 4 treatment groups: infrared beak treatment at 1 day of age; hot-blade trimming at 1 day of age; hot-blade trimming at 7 days of age and; an untrimmed control treatment. The birds will be housed in 6-bird/cage (67 in 2/bird) under the standard management. Mortality will be recorded over the time. Samples (brain, blood, and beak) and behaviors will be collected at 1, 2, 5, 10, 18, 25, 35, 45 and 60 weeks post-trimming (n=12 calculated based an alpha = 0.05 and 1-ß= 0.80). Brain and blood samples will be analyzed for the changes of pain-associated neurotransmitters and neuropeptides using HPLC or RIA, respectively. Beak samples will be analyzed for traumatic-associated changes of nerve fibers and neuroma formation using histological staining, immuncytochemistry, and the microscope imaging system. Both general circadian and pain-test behavior will be recorded using a 16 channel digital video recording (DVR) system. Behavioral data will be collected from using two methods; 5-min scan samples and continuous focal sampling. In addition, physical data, body weight, feather score, feed intake, egg production, and feed efficiency, will be collected in the study. Behavior, neuroendocrine function, and production will be compared statistically among the treatments.
3. Progress Report:
This serves as the final report. This study was conducted to investigate pain in chickens after the two beak trimming methods: infrared vs. hot blade. A total of 1,056, 1-day-old, chicks were randomly distributed among 4 treatment groups: infrared beak treatment at 1 day of age; hot-blade trimming at 1 day of age; hot-blade trimming at 7 days of age and; an untrimmed control treatment. The microscopic investigation of the structural changes in the beak stumps following histological and immunological strains indicated that both infrared and hot blade beak trimming conducted at day 1 and 7 did not cause tangled mass of abnormal nerve fibers. Compared to hot blade trimmed beaks, infrared trimmed beaks had more nerve fibers with less scar tissue at various stages, which indicated that infrared beak trimming caused less tissue damage. Pain tests indicated that hens trimmed with an infrared technology expressed less pain than hens which were trimmed with a hot-blade. Our research identified infrared beak trimming as a less painful alternative which is currently adopted by the poultry industry.