Start Date: Oct 01, 2010
End Date: Aug 31, 2012
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 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 on 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 MCID 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 DVDs 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.