Nicol C J, Brown S N, Glen E, Pope S J, Short F J, Warriss P D, Zimmerman P H, Wilkins L J
School of Veterinary Science, University of Bristol, Langford House, Langford BS40 5DU and ADAS Gleadthorpe, Meden Vale, Mansfield, Notts NG20 9PF, England.
Br Poult Sci. 2006 Apr;47(2):135-46. doi: 10.1080/00071660600610609.
Management practices, stocking rate and flock size may affect laying hen welfare but there have been few replicated studies in commercial non-cage systems that investigate this. This study used a broad range of physical and physiological indicators to assess the welfare of hens in 36 commercial flocks. Six laying period treatments were examined with each treatment replicated 6 times. It was not possible to randomly allocate treatments to houses, so treatment and house were largely confounded. Three stocking rates were compared: 7 birds/m(2) (n = 2450), 9 birds/m(2) (n = 3150) and 12 birds/m(2) in either small (n = 2450) or large (n = 4200) flocks. In addition, at 12 birds/m(2), in both small and large flocks, birds were subjected to either standard (SM) or modified (MM) management. MM flocks had nipple drinkers and no nest-box lights. Bone strength, fracture incidence, heterophil:lymphocyte (H:L) ratio, live weight, organ weights, serum creatine, serum osmolality, muscle pH and faecal corticosterone were measured on samples of birds at the end of the rearing period and at the end of lay. During the laying period, mortality, production and integument condition were recorded at regular intervals. Birds housed at 9 birds/m(2) had higher mortality than birds housed at 12 birds/m(2) by the end of lay, but not higher than birds housed at 7 birds/m(2). Birds housed at 7 and 9 birds/m(2) had lower percent liver weight, and worse plumage condition than most of the 12 bird/m(2) treatments. Modified management tended to improve plumage condition. There were no clear effects of flock size on the welfare indicators recorded. At the end of the rearing period fracture incidence was almost negligible and H:L ratio was within a normal range. By the end of lay fracture incidence was 60% and H:L ratio was high, with no treatment effect for either measure. This, together with information on faecal corticosterone, feather loss and mortality, suggests that the welfare of birds in all treatments was relatively poor by the end of lay.
管理措施、饲养密度和鸡群规模可能会影响蛋鸡的福利，但在商业非笼养系统中，很少有重复性研究对此进行调查。本研究使用了广泛的身体和生理指标来评估36个商业鸡群中母鸡的福利。研究考察了六个产蛋期处理，每个处理重复6次。由于无法将处理随机分配到鸡舍，因此处理和鸡舍在很大程度上相互混淆。比较了三种饲养密度：每平方米7只鸡（n = 2450）、每平方米9只鸡（n = 3150）和每平方米12只鸡，鸡群规模分为小群（n = 2450）或大群（n = 4200）。此外，在每平方米12只鸡的情况下，无论小群还是大群，鸡群都采用标准管理（SM）或改良管理（MM）。MM鸡群使用乳头式饮水器，且没有巢箱灯。在育雏期结束时和产蛋期结束时，对鸡的样本测量了骨强度、骨折发生率、嗜异性粒细胞：淋巴细胞（H:L）比值、体重、器官重量、血清肌酸、血清渗透压、肌肉pH值和粪便皮质酮。在产蛋期，定期记录死亡率、产蛋量和体表状况。到产蛋期结束时，每平方米饲养9只鸡的鸡群死亡率高于每平方米饲养12只鸡的鸡群，但不高于每平方米饲养7只鸡的鸡群。每平方米饲养7只和9只鸡的鸡群肝脏重量百分比低于大多数每平方米饲养12只鸡的处理组，且羽毛状况更差。改良管理倾向于改善羽毛状况。鸡群规模对所记录的福利指标没有明显影响。在育雏期结束时，骨折发生率几乎可以忽略不计，H:L比值在正常范围内。到产蛋期结束时，骨折发生率为60%，H:L比值较高，两种测量方法均无处理效应。这与粪便皮质酮、羽毛脱落和死亡率的信息一起表明，到产蛋期结束时，所有处理组鸡的福利都相对较差。
