Bari Md Saiful, Laurenson Yan C S M, Cohen-Barnhouse Andrew M, Walkden-Brown Stephen W, Campbell Dana L M
Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Armidale, New South Wales, Australia.
School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia.
PeerJ. 2020 Mar 6;8:e8720. doi: 10.7717/peerj.8720. eCollection 2020.
In Australia, free-range layer pullets are typically reared indoors, but adult layers go outdoors, and this mismatch might reduce adaptation in laying environments. Enrichments during rearing may optimise pullet development and subsequent welfare as adult free-range hens. In the outdoor environment, hens may have greater opportunities for exercise and natural behaviours which might contribute to improved health and welfare. However, the outdoor environment may also result in potential exposure to parasites and pathogens. Individual variation in range use may thus dictate individual health and welfare. This study was conducted to evaluate whether adult hens varied in their external and internal health due to rearing enrichments and following variation in range use. A total of 1386 Hy-Line Brown chicks were reared indoors across 16 weeks with three enrichment treatments including a control group with standard housing conditions, a novelty group providing novel objects that changed weekly, and a structural group with custom-designed structures to increase spatial navigation and perching. At 16 weeks of age the pullets were moved to a free-range system and housed in nine identical pens within their rearing treatments. All hens were leg-banded with microchips and daily ranging was assessed from 25 to 64 weeks via radio-frequency identification technology. At 64-65 weeks of age, 307 hens were selected based on their range use patterns across 54 days up to 64 weeks: indoor (no ranging), low outdoor (1.4 h or less daily), and high outdoor (5.2-9 h daily). The external and internal health and welfare parameters were evaluated via external assessment of body weight, plumage, toenails, pecking wounds, illness, and post-mortem assessment of internal organs and keel bones including whole-body CT scanning for body composition. The control hens had the lowest feather coverage ( < 0.0001) and a higher number of comb wounds ( = 0.03) than the novelty hens. The high outdoor rangers had fewer comb wounds than the indoor hens ( = 0.04), the shortest toenails ( < 0.0001) and the most feather coverage ( < 0.0001), but lower body weight ( < 0.0001) than the indoor hens. High outdoor ranging decreased both body fat and muscle (both < 0.0001). The novelty group had lower spleen weights than the control hens ( = 0.01) but neither group differed from the structural hens. The high outdoor hens showed the highest spleen ( = 0.01) and empty gizzard weights ( = 0.04). Both the rearing enrichments and ranging had no effect on keel bone damage (all ≥ 0.19). There were no significant interactions between rearing treatments and ranging patterns for any of the health and welfare parameters measured in this study ( ≥ 0.07). Overall, rearing enrichments had some effects on hen health and welfare at the later stages of the production cycle but subsequent range use patterns had the greatest impact.
在澳大利亚，散养蛋鸡雏鸡通常在室内饲养，但成年蛋鸡会到户外，这种不匹配可能会降低蛋鸡对产蛋环境的适应性。育雏期间的环境优化措施可能会优化雏鸡发育，并提升成年散养母鸡的福利水平。在户外环境中，母鸡可能有更多机会进行运动和展现自然行为，这可能有助于改善健康和福利状况。然而，户外环境也可能导致潜在的寄生虫和病原体暴露风险。因此，个体在户外活动范围的差异可能决定个体的健康和福利状况。本研究旨在评估成年母鸡的外部和内部健康状况是否因育雏环境优化措施以及随后户外活动范围的变化而有所不同。总共1386只海兰褐雏鸡在室内饲养16周，采用三种环境优化处理方式，包括一个标准饲养条件的对照组、一个每周更换新奇物品的新奇组，以及一个配备定制结构以增加空间导航和栖息功能的结构组。16周龄时，雏鸡被转移到散养系统，并按照育雏处理方式饲养在九个相同的鸡舍中。所有母鸡都佩戴了带有微芯片的脚环，并通过射频识别技术在25至64周龄期间评估每日户外活动范围。在64 - 65周龄时，根据54天直至64周龄的户外活动范围使用模式选择了307只母鸡：室内（无户外活动）、低户外（每天1.4小时或更少）和高户外（每天5.2 - 9小时）。通过对体重、羽毛、脚趾甲、啄伤、疾病的外部评估以及对包括全身CT扫描以评估身体组成的内部器官和龙骨的死后评估，来评估外部和内部健康及福利参数。对照组母鸡的羽毛覆盖率最低（<0.0001），且鸡冠伤口数量高于新奇组母鸡（=0.03）。高户外活动范围的母鸡鸡冠伤口比室内母鸡少（=0.04），脚趾甲最短（<0.0001），羽毛覆盖率最高（<0.0001），但体重低于室内母鸡（<0.0001）。高户外活动范围会降低体脂和肌肉量（两者均<0.0001）。新奇组母鸡的脾脏重量低于对照组母鸡（=0.01），但两组与结构组母鸡均无差异。高户外活动范围的母鸡脾脏重量最高（=0.01），砂囊空重最高（=0.04）。育雏环境优化措施和户外活动范围对龙骨损伤均无影响（所有p≥0.19）。在本研究中测量的任何健康和福利参数方面，育雏处理方式和活动范围模式之间均无显著交互作用（所有p≥0.07）。总体而言，育雏环境优化措施在生产周期后期对母鸡健康和福利有一定影响，但随后的活动范围使用模式影响最大。
