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$\le$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.

由于对人类药物治疗中抗菌素耐药性的关注日益增加，美国肉鸡行业正朝着无抗生素（ABF）生产的方向发展。考虑到ABF日粮与常规日粮之间的性能差异，可能会导致进食和饮水行为发生变化。这项研究的目的是在4种放养密度（SD）下，分别以ABF日粮和含抗生素生长促进剂的日粮（AGP日粮），即27日（27SD），29日（29SD）， 33（33SD）和kg·m ^-2（39SD）。每头饲喂器（具有14个饲喂器插槽）的资源补贴范围为50到72只禽类，每个乳头饮水器的资源配额为11到12只禽类。使用超高频射频识别系统，在30至35 D年龄连续监测每个处理组合中15只肉鸡的行为。结果表明，饲喂ABF日粮的肉鸡的饲喂时间（62.7 min·鸟^-1  D ^-1）和饲喂次数（52次·鸟^-1  D ^-1）显着减少（P$\le$0.02）比采用AGP饮食的鸟类（85.1分钟·鸟类^-1  D ^-1和62倍·鸟类^-1  D ^-1）。不同治疗方法之间的鸟类饮水行为相似。行为变化的系数在各处理之间无显着差异，表明饮食和SD对这些行为的鸡群均匀性没有影响。在任何饮食和标准水平下，饲喂者和饮者的利用率均低于40％，表明有足够的资源补贴。结论是：1）饮食和管理的变化可能会改变某些肉鸡的行为，并且2）结果为基准化的行为数据提供了标准化的标准，以实现高效，福利和健康的肉鸡生产。