Functional housing systems for high welfare in laying hens: promoting natural behaviors in safe environments

英国有3600万只蛋鸡，产100亿个鸡蛋，零售价值达10亿英镑。在欧盟，3.35亿只母鸡生产100亿欧元，而全球有近50亿只母鸡生产超过1万亿个鸡蛋。鸡蛋生产是主要的财富创造者，也是全球粮食生产的关键要素。在欧盟，电池笼系统已被禁止，大部分生产转向自由放养系统（FRS）。包括印度和美国在内的许多其他国家也提出了类似的立法。FRS为蛋鸡提供了许多健康和福利益处，但最近出现了对蛋鸡福利和生产的两个主要威胁，需要紧急采取行动。在FRS中，龙骨骨折平均影响60%的母鸡，有些系统甚至高达90%。这些都是痛苦的，降低了生产力和利润。英国每年有多达2000万只母鸡患有龙骨骨折，农场动物福利委员会认为这是母鸡福利中最严重的问题。在超过四分之三的FRS中，多达一半的母鸡受到有害啄毛（IFP）的影响，导致疼痛、产蛋量下降、饲料消耗增加，并经常导致同类相食和死亡。修剪喙是控制IFP的主要手段，目前在许多欧盟国家被禁止，英国将于2016年颁布禁令，这使得生产商没有有效的控制手段。因此，需要采取紧急行动，制定另一项战略，以减少因卡因卡的水平。蛋鸡的福利仍然是公众严重关注的问题，超过75%的英国和欧盟公民认为母鸡的福利不足。我们已经表明，在正常活动期间与房屋系统内的结构的影响是龙骨骨折的主要原因。然而，危险的住房结构不能完全消除，减少活动，就像在养鸡场看到的那样，严重损害了骨骼功能。我们已经证明，FRS母鸡更多地利用了这个范围，更有可能保持无骨折。然而，在许多系统中，测距的使用仍然很低，测距的潜在好处还没有实现。我们假设，增加射程使用将促进活动远离危险结构，提高骨骼强度和骨骼功能，但避免产生龙骨损伤的有害影响。同样，我们和其他研究人员也指出，距离可以显著降低IFP，在使用大量距离的系统中，IFP下降了89%。因此，我们假设增加范围使用的行动将减少IFP的发生率和严重程度，并鼓励自然觅食行为。目的是确定在安全环境中增加活动和自然行为的措施是否会显著减少蛋鸡的龙骨骨折和IFP。然而，放养和活动可能有其他健康和生产后果，这些将在鸡群和个人层面进行检查，使我们能够确定放养对母鸡整体健康的影响以及对生产者的经济影响。这项研究将结合视频监控、福利评估、BBSRC之前资助的研究中开发的尖端活动记录，以及领先的动物监测专家Biotrack提供的轻型监测技术。我们将比较正常的FRS、增强的FRS和畜舍系统，以获得个体和畜群活动、范围和行为的广度。这将首次允许对商业生产单位的鸡群和个体母鸡的范围使用和活动进行评估，由我们的工业合作伙伴，英国领先的鸡蛋生产商之一Stonegate提供。通过检查啄羽毛行为、羽毛得分和龙骨骨折的福利结果，我们可以评估与骨折发生率和IFP水平的关系。我们将进一步确定运动与骨骼的生物力学、代谢、生理和放射学变化之间的关系，以更好地了解运动如何影响鸡的骨骼功能。

There are 36 million UK laying hens producing 10 billion eggs with a retail value of £1 billion. In the EU 335 million hens generate E10 billion, and globally there are nearly 5 billion hens producing over 1 trillion eggs. Egg production is a major wealth creator and a key element of global food production. In the EU, battery cage systems have been banned, with much of the production switched to free range systems (FRS). Similar legislation is proposed in many other countries, including India and the USA. FRS provide many health and welfare benefits to laying hens, however two major threats to welfare and production have recently emerged which require urgent action. Keel bone fractures effect on average 60% of hens in FRS, with some systems as high as 90%. These are painful and reduce productivity and profit. With up to 20 million UK hens suffering from keel fractures each year, the Farm Animal Welfare Committee regard this as the most serious problem of hen welfare. Injurious feather pecking (IFP) affects as many as half the hens in over three quarters of all FRS, resulting in pain, decreased egg production, increased feed consumption, and often leading to cannibalism and death. Beak trimming, the main means of controlling IFP, is now banned in a number of EU countries, with a UK ban proposed for 2016, leaving producers with no effective means of control. Urgent action is therefore needed to devise an alternative strategy to reduce levels of IFP. Welfare in laying hens remains a serious public concern, with over 75% of UK and EU citizens regarding hen welfare as inadequate.We have shown that impacts with structures within housing systems during normal activities are the major cause of keel fractures. However, hazardous housing structures cannot be entirely eliminated, and reducing activity, as seen in battery hens, seriously impairs skeletal function. We have shown that FRS hens making greater use of the range are more likely to remain fracture-free. However, range use in many systems remains very low, and the potential benefits of ranging are not being realised. We hypothesise that increased range use will promote activity away from hazardous structures, improving bone strength and skeletal function, but avoiding injurious impacts which generate keel damage. Similarly, we and others have indicated that ranging significantly reduces IFP, with an 89% drop in systems with substantial range use. Thus we hypothesise that action to increase range use will reduce incidence and severity of IFP, and encourage natural foraging behaviours.The aim is to determine whether actions to increase activity and natural behaviours in a safe environment will substantially and significantly reduce keel fractures and IFP in laying hens. However, ranging and activity may have other health and production consequences, and these will be examined at flock and individual level, allowing us to determine the effects of range use on the overall wellbeing of hens and the economic impact for the producers.This study will combine video monitoring, welfare assessments, cutting-edge activity logging developed in previous BBSRC funded research, and light-level monitoring technology provided by Biotrack, a leading animal monitoring specialist. We will compare normal FRS, enhanced FRS and barn systems to get a breadth of individual and flock activity, ranging and behaviours. For the first time, this will allow evaluation of range use and activity in flocks and individual hens in commercial production units, provided by Stonegate, our Industrial Partner, one of the UK's leading egg producers. By examining welfare outcomes of feather pecking behaviour, plumage scores and keel fractures, we can assess relationships with fracture incidence and IFP levels. We will further determine how activity relates to biomechanical, metabolic, physiological and radiological changes in bone, to better understand how exercise influences skeletal function in chickens.