A Mathematical Modelling approach to defining factors which cause keel fractures in free range laying hens

蛋鸡的骨骼健康是一个主要问题，它降低了盈利能力，造成了公众对鸡蛋生产的不良看法，并影响了消费者的选择。最近的研究表明，高达80%的自由放养母鸡患有龙骨骨折。因此，尽管电池笼子带来了许多福利，但自由放飞系统带来了独特而紧迫的经济和福利问题。2012年欧盟对电池笼系统的禁令要求将1800万只鸡“转移”到替代系统中，其中大部分是自由放养的--这相当于英国每年可能多出1400万只母鸡患有骨折。业界认为这是不可持续的，DEFRA认为这是一个主要的福利问题。英国的鸡蛋生产是重要的财富创造者，每年价值8.68亿GB，但其狭窄的利润率使其特别容易受到市场力量的影响。英国完全遵守2012年的电池笼禁令，但大多数欧盟国家并非如此，据预测，23%的欧盟鸡蛋将是非法生产的，廉价进口对英国产业尤其构成威胁。因此，这些福利和生产力问题的解决特别及时，属于BBSRC的优先领域，包括食品安全、动物健康、受管理动物的福利、数据驱动生物学、与用户的协作研究、生物科学的系统方法、牲畜生产和研究以告知公共政策。房屋结构内的碰撞被认为是龙骨骨折的主要原因。然而，在观察骨折发生时遇到的困难阻碍了对与母鸡相关的关键因素或决定骨折发生或严重程度的特定影响的清楚了解。这项研究将在体外冲击测试系统中复制龙骨骨折，允许精确量化诸如重量、年龄、龙骨强度和顺应性等鸟类因素，以及诸如冲击能量和材料顺应性等碰撞因素，并将这些因素与龙骨骨折的发生和严重程度直接相关。我们将使用一种新的数学建模方法，该方法将定义哪些因素影响骨折的发生，并提供对给定特征的单个鸟或家禽群的骨折的“风险评估”。该模型将使用放置在两个相反的住房环境中的活鸟进行验证，这些环境旨在提供低能量和高能量飞行。鸟儿将安装“撞击记录器”(已经与撞击测试系统相关联)，以确定与飞行受阻相关的能量。个别鸟类因素将在住房期间结束时确定(如上所述)，并对龙骨断裂进行评估。通过这种方式，模型预测将针对单个禽类和住房系统层面的实际裂缝进行测试。农场研究将确定特定商品房类型的动能分布，我们之前已经表明，这些类型的房屋具有很大不同的破碎率。我们的影响监测器将提供房屋风险的物理测量，并允许我们测试该模型在预测商业环境中的断裂情况。这项研究的结果将使商业房屋系统能够对其预测的龙骨断裂风险进行功能性评估，并将确定生产者或政策制定者可能针对的房屋设计或鸟类生理的关键要素，以降低断裂率。这种前瞻性的“风险评估”可以用来在几天而不是几个月内评估住房变化的影响。因此，面对欧盟禁止电池笼系统带来的困难，这项研究有可能极大地改善蛋鸡的健康和福利，提高公众对鸡蛋生产的态度，以及英国蛋业的盈利能力和可持续性。

Skeletal health in laying hens is a major problem, reducing profitability, creating a poor public perception of egg production, and influencing consumer choice. Recent studies showed up to 80% of free range hens suffer keel bone breakage. Thus, despite many welfare benefits over battery cages, free range systems present unique and urgent economic and welfare problems. The 2012 EU ban on battery cage systems required that 18 million birds be "transferred" to alternative systems, mostly free range - equating to a potential 14 million more hens suffering bone breakage each year in the UK. The industry views this as unsustainable, and DEFRA regards this as a major welfare concern. Egg production in the UK is an important wealth creator, worth £868 million/year, but its narrow profit margins make it particularly vulnerable to market forces. The UK is entirely compliant with the 2012 battery cage ban, however this is not the case for most EU countries, and it is forecast that 23% of EU eggs will be produced illegally, with cheap imports a particular threat to the UK industry. Therefore resolution of these welfare and productivity problems is particularly timely, and falls within the BBSRC priority areas of Food Security, Animal Health, Welfare of Managed Animals, Data Driven Biology, Collaborative Research with Users, Systems Approaches to the Biosciences, Livestock Production and Research to Inform Public Policy.Collisions within housing structures are believed to be the principle cause of keel fractures. However, difficulties in observing breaks as they happen prevent a clear understanding of the critical factors associated either with the hen or the particular impact which determines the occurrence or severity of a fracture. A lack of knowledge as to which factors are causal in keel fractures, prevents steps being taken to alleviate these in an informed and objective manner.This study will replicate keel fractures in an ex-vivo impact testing system, allowing precise quantitation of bird factors such as weight, age, keel strength and compliance, and collision factors such as impact energy and material compliance, and directly relate these to the occurrence and severity of keel fractures. We will use a novel mathematical modelling approach that will define which factors influence fracture occurrence and provide a "risk assessment" of fractures in an individual bird or housed flock of given characteristics. The model will be validated using live birds placed in two contrary housing environments designed to provide low and high energy flights. Birds will be fitted with "impact loggers" (already correlated with the impact testing system) to determine the energies associated with arrested flights. Individual bird factors will be determined (as described above) at the end of the housing period, and keel breaks assessed. In this way the model predictions will be tested against actual fractures at individual bird and housing system level. On-farm studies will determine kinetic energy profiles of particular commercial housing types which we have previously shown to have widely differing fracture rates. Our impact monitors will provide a physical measure of housing risk, and allow us to test the model in predicting fractures in commercial settings.The outcomes from this study will allow commercial housing systems to be functionally assessed for their projected keel breakage risk, and will identify key elements of housing design or bird physiology that may be targeted by producers or policy makers to reduce fracture rates. Such a prospective "risk assessment" could be used to evaluate effects of housing changes within days rather than months. Therefore this study has the potential to greatly improve the health and welfare of laying hens, the public attitudes to egg production, and the profitability and sustainability of the UK egg industry in the face of difficulties arising from the EU ban on battery cage systems.