ARS | Publication request: BEHAVIOR OF CHICKS AFTER BEAK TRIMMING: INDICATORS OF PAIN AND WELFARE

Submitted to: World Poultry
Publication Type: Abstract Only
Publication Acceptance Date: December 4, 2003
Publication Date: N/A

Technical Abstract: Beak trimming (BT) is a routine practice in the poultry industry to limit the impact of feather pecking and cannibalism. Previous studies have shown that chickens trimmed at or older than 5 weeks of age, experience acute pain that lasts for at least a few days and may also cause chronic pain. The present study examined if chickens trimmed at 1 day of age experience pain, and if the pain persists using a combination of behavioral and neurological procedures. Sixteen W-36 White Leghorn chicks at 1 day of age were randomly divided into sham control and experimental groups. Experimental chicks were trimmed using a precision trimmer (Lyon Electric Co, Inc., USA). Chicks were placed in individual cages at 144 square inches. Food and water were available ad lib. Light period was 16 hours daily. Behavior was filmed for the entire light period on days 1, 7, 14 and 19 using time-lapse video recorders. Scan sampling at 5-min intervals was used to record activity and pecking (192 observations per chick). Plasma corticosterone (CORT) was measured using a radio immuno assay kit (ICN Inc., USA). Behavior was analyzed using a mixed model ANOVA with treatment as a between subject effect, and age as a within subject effect (SPSS version 10.1). Concentrations of CORT were analyzed using post-hoc paired t-tests. The study found that, compared to controls, trimmed chicks were more inactive in the first day after trimming (ANOV, F1,14 = 3.1, P<0.05), and pecked less during the period of 7-14 days post-trimming (ANOV, F1,14 = 2.9, P<0.05). Trimmed chicks had higher CORT concentrations than those of sham controls on day 1 only (P<0.05). Inactivity and higher CORT levels in trimmed chicks could be related to stress resulting from beak trimming. Reduced pecking may arise from the chicks guarding the beak stump from painful contact and stimulation. The results suggest that hot-blaze beak trimming causes an early stress response and pain sensation. Pain sensation may persist; at least, during the period of the first 3 weeks following beak trimming.