Campbell Dana L M, Horton Brian J, Hinch Geoff N
Agriculture and Food, CSIRO, New England Highway, Armidale, NSW 2350, Australia.
School of Environmental and Rural Science, University of New England, Armidale, NSW 2350, Australia.
Animals (Basel). 2018 Nov 16;8(11):210. doi: 10.3390/ani8110210.
Free-range laying hen systems provide individuals a choice between indoor and outdoor areas where range use may be socially influenced. This study used radio-frequency identification technology to track the ranging of individually-tagged hens housed in six experimental free-range pens from 28 to 38 weeks of age (46⁻50 hens/pen). All daily visits to the range were used to study group behaviour. Results showed that 67.6% (SD = 5.0%) of all hen movements through the pop-holes outdoors or indoors were following the movement of another hen ('pop-hole-following') compared to only 50.5% of movements in simulated random data. The percentage overlap in time that all combinations of hen pairs within each pen spent simultaneously outdoors or indoors showed a median value of overlap greater than the 90th percentile of random data. Pens housing hens that had been provided variable enrichments from 4 to 21 days (n = 3 pens) showed higher 'pop-hole-following' behaviour and a higher percentage of hen-pair association compared to hens reared in non-enriched conditions (n = 3 pens). These results show that birds in each free-range pen were primarily a cohesive flock and early enrichment improved this social cohesiveness. These results have implications for understanding free-range flock-level behaviour.
散养蛋鸡系统为个体提供了在室内和室外区域之间进行选择的机会，其中室外活动的使用可能会受到社会因素的影响。本研究使用射频识别技术跟踪了饲养在六个实验性散养围栏中的个体标记母鸡在28至38周龄（每围栏46 - 50只母鸡）期间的活动范围。所有每日到室外区域的访问都用于研究群体行为。结果表明，所有母鸡通过室外或室内出入口的移动中，有67.6%（标准差 = 5.0%）是跟随另一只母鸡的移动（“跟随出入口移动”），而在模拟随机数据中这一比例仅为50.5%。每个围栏内所有母鸡对同时在室外或室内花费时间的重叠百分比显示，重叠中位数大于随机数据的第90百分位数。与在未进行丰富饲养条件下饲养的母鸡（n = 3个围栏）相比，在4至21天内接受了不同丰富饲养的母鸡（n = 3个围栏）表现出更高的“跟随出入口移动”行为和更高的母鸡对关联百分比。这些结果表明，每个散养围栏中的鸡主要是一个有凝聚力的群体，早期丰富饲养改善了这种社会凝聚力。这些结果对于理解散养群体水平的行为具有启示意义。
