Effects of antibiotic-free diet and stocking density on male broilers reared to 35 days of age. Part 2: feeding and drinking behaviours of broilers

Abstract

Summary The U.S. broiler industry is trending toward antibiotic-free (ABF) production because of increasing concerns on antimicrobial resistance in human medicinal treatments. Given the differences in performance observed between ABF diets and conventional diets, changes in feeding and drinking behaviors may result. The objective of this study was to characterize feeding and drinking behaviors of male broilers fed with ABF diet vs. diet containing antibiotic growth promoter (AGP diet) under 4 stocking densities (SD), that is 27 (27SD), 29 (29SD), 33 (33SD), and kg·m−2 (39SD). Resource allowances ranged from 50 to 72 birds per tube feeder (with 14 feeder slots) and 11 to 12 birds per nipple drinker. Behaviors of 15 broilers in each treatment combination were monitored continuously at 30 to 35 D of age using an ultra-high frequency radio frequency identification system. The results show that feeding time (62.7 min·bird−1 D−1) and feeder visits (52 times·bird−1 D−1) of broilers with ABF diet were significantly less (P ≤ 0.02) than birds with AGP diet (85.1 min·bird−1 D−1 and 62 times·bird−1 D−1). Bird drinking behaviors were similar among treatments. Coefficient of variation of the behaviors was not significantly different among treatments, suggesting unaffected flock uniformity of these behaviors by diet and SD. Feeder and drinker utilization ratios were less than 40% at any diet and SD levels, indicating sufficient resource allowances. It is concluded that 1) changes in diet and management may alter certain broiler behaviors and 2) the results offer benchmark behavioral data for standardization of resource allowances toward efficient, welfare, and healthy broiler production.