Animal Welfare and Behaviour Group, School of Veterinary Sciences, University of Bristol, Langford, Bristol, BS40 5DU, UK.
Vet Rec. 2012 Jun 23;170(25):647. doi: 10.1136/vr.100728. Epub 2012 Jun 7.
The average mortality for end of lay hens dead on arrival (DOA) was 0.27 per cent (median 0.15 per cent) in a survey of 13.3 million hens transported during 2009. A statistical model of the data indicated main risk factors for DOA to be slaughter plant, distance travelled and external air temperature, with longer journeys and low external air temperatures increasing the risk. Other highly significant risk factors (P<0.001) related to the condition of the birds on farm, where an increased risk of DOA was positively associated with poor feather cover, lower body weight, cumulative mortality of the flock and poor health (indicated by a high proportion of the load rejected at the plant for traumatic injury and disease state). However, the data indicate that by taking risk factors into consideration it is possible to transport hens up to 960 km with low losses in temperate conditions. Mean levels of on-farm mortality, during the laying period, for a total of 1486 flocks were significantly lower in cages (5.39 per cent) than in barn (8.55 per cent), free-range (9.52 per cent) or organic flocks (8.68 per cent) according to producer records a median of seven days before depopulation, with considerable variation between flocks in all systems.
在 2009 年对 1330 万只运输鸡进行的调查中，死亡到达（DOA）的淘汰母鸡的平均死亡率为 0.27%（中位数为 0.15%）。对数据的统计模型表明，DOA 的主要风险因素是屠宰场、行驶距离和外部空气温度，长途运输和外部空气温度较低会增加风险。其他高度显著的风险因素（P<0.001）与农场中鸡的状况有关，DOA 的风险增加与羽毛覆盖不良、体重降低、禽群累计死亡率和健康状况差（以在工厂因创伤和疾病状态而拒收的负荷比例高为指标）呈正相关。然而，数据表明，通过考虑风险因素，可以在温带条件下以低损失运输长达 960 公里的母鸡。根据生产者记录，在淘汰前七天的中位数，在笼养（5.39%）、谷仓饲养（8.55%）、自由放养（9.52%）或有机饲养（8.68%）的母鸡在产蛋期间的农场死亡率总平均值明显更低，所有系统中鸡群之间的差异都很大。
