Cunningham D L, van Tienhoven A, Gvaryahu G
Department of Poultry and Avian Sciences, Cornell University, Ithaca, New York 14853.
Poult Sci. 1988 Mar;67(3):399-406. doi: 10.3382/ps.0670399.
The effect of two cage population sizes (four vs. six/cage) and two cage area treatments (316 cm2 vs. 406 cm2/bird) were compared in a nonconfounded design while maintaining feeder space constant (8.9 cm/bird) for egg production performances and behavioral and physiological indicators of well-being of laying hens. Egg production rates were determined for all members of each cage group (palpations at 48 to 50 wk) and on a cage group basis (20 to 60 wk). Heart weights, plasma corticosterone levels, durations of tonic immobility (TI), and plumage conditions were compared for top and bottom birds in the dominance ranks. Significant reductions in egg production were observed for low ranking hens in the high density (4 and 6/316-cm2) treatments. In addition, high ranking hens of the 6/316-cm2 treatment produced fewer eggs than high ranking hens in the 4/316-cm2 treatment. When high and low ranking individuals were housed in single-hen cages, egg production was improved relative to performances in the social environments. Heart weights of hens, as a percentage of body weight, were increased in the low ranking hens and for hens in the smaller cage size. Plasma corticosterone did not prove to be a useful indicator of well-being. Low ranking individuals had greater durations of TI but differences in feather condition were not detected. The results support the contention that appropriate population sizes and cage space allocations can be determined that will optimize the performance and welfare of layers in cage environments.
在一项无混杂因素的设计中，比较了两种笼养种群规模（每笼4只与6只）和两种笼养面积处理方式（每只鸡316平方厘米与406平方厘米），同时保持采食空间恒定（每只鸡8.9厘米），以研究蛋鸡的产蛋性能以及行为和生理健康指标。测定了每个笼组所有成员的产蛋率（48至50周龄时触摸检查）以及基于笼组的产蛋率（20至60周龄）。比较了优势等级中处于顶部和底部的鸡的心脏重量、血浆皮质酮水平、强直静止时间（TI）和羽毛状况。在高密度（4只和6只/316平方厘米）处理中，低等级母鸡的产蛋量显著下降。此外，6/316平方厘米处理组的高等级母鸡比4/316平方厘米处理组的高等级母鸡产蛋量少。当将高等级和低等级个体饲养在单只鸡笼中时，产蛋量相对于群居环境有所提高。低等级母鸡以及较小笼养面积中的母鸡，其心脏重量占体重的百分比增加。血浆皮质酮并未被证明是一个有用的健康指标。低等级个体的TI持续时间更长，但未检测到羽毛状况的差异。结果支持这样的观点，即可以确定合适的种群规模和笼养空间分配，以优化笼养环境中蛋鸡的性能和福利。
