Effect of partial comb and wattle trim on pullet behavior and thermoregulation,1

The wattles and comb of chickens are important for thermoregulation allowing for heat exchange during high temperatures. These integumentary tissues are sometimes trimmed to prevent tears if caught on cage equipment and to also improve feed efficiency; however, the procedure itself could be painful to chicks. Our objective was to determine the effect of trimming the comb and wattles on behavior, BW, feed usage, and the surface temperature of pullets. The wattles and comb of Leghorns were partially trimmed at 21 d age (n = 6 cages, 13 chicks each) with another 6 cages serving as controls. Behaviors were recorded 3 times daily for 1 h starting at 0800, 1200, and 1500 using instantaneous scan sampling observations conducted every 5 min prior to, on the d of, and after the trim. Group BW at 21, 28, and 36 d age and the amount of feed used for 7 d beginning at 21 and 29 d age were measured per cage. At 1300 h on d before and after the trim, thermal images of the pullet's beak, comb, eye, wattle, and shank were randomly taken on 3 pullets/cage. Smaller proportions of trimmed chicks were eating and greater proportions were sitting on the d of the trim as compared to the controls with the opposite trend occurring on 4 d post-trim (treatment by age interaction, P = 0.03 and 0.0001, respectively). Standing behavior differed only on the d of the trim where smaller proportions of trimmed pullets stood as compared to intact controls (treatment by age interaction, P = 0.0002). Trimming the comb and wattles did not affect preening, running, BW, feed utilization, and the surface temperature of the pullet. The indices of behavior suggest that on the d of the trim, pullets may have experienced temporary distress, but they returned to normal behavior by 5 h post-trim with no long-term effect on BW, feed usage, or surface body temperature.