Why do hens smother? An investigation into the causes and consequences of smothering

母鸡为什么会窒息？

• 批准号: BB/T001747/1
• 负责人: Lucy Asher
• 金额: $ 68.43万
• 依托单位: Newcastle University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FT001747%2F1
• 关键词: Why; do; hens; smother; investigation

There can be no egg farmer who wants to walk into a chicken house and find a pile of dead birds, only to know the same event could happen again tomorrow and the next day, without being able to prevent it. This is the impact of smothering, a strange behaviour whereby hens pile on top of each other causing deaths of chickens at the bottom of the pile. No-one really understands why chickens do this and often they appear to move slowly and calmly in the lead up to smothering. Naturally, farmers who produce eggs would like to reduce this behaviour, but it doesn't happen when they are present in the farm watching the birds. It happens intermittently and is hard to predict. New approaches are therefore urgently needed to understand this behaviour. The behaviour and motivations of birds during these smothering events is of great interest to scientists because animals don't often cause the death of other animals of the same species in such an apparently calm manner. This research aims to investigate when, where and how smothering happens, and the effect smothering has on the chickens that survive. The fact that smothering is unpredictable means that a large number of farms are needed in order to study this behaviour. Working with an egg producing company we will have access to 110 flocks of birds. These all have a monitoring system, Birdbox, which records information about the environment of the hens (e.g. ventilation and temperature), food and water intake, egg production, and numbers and causes of hen deaths. We will also gather further information on whether these chickens were stressed when they were still chicks, details of the barns where they live, at what time smothering events occur and where in the barn they happen. All this information will be used find the potential causes of smothering and to see if there could be early warning signs before it happens. Whilst useful for understanding the development of smothering behaviour, these analyses by themselves won't identify the immediate cues that cause chickens to move in ways which smother others, or indeed what movements cause smothering. To address this we will place heart rate monitors on chickens and film smothering events using thermal and standard cameras. The thermal cameras will allow us to automatically measure movements of chickens to be able to create a realistic simulation of smothering. The simulation of smothering will allow us to understand what it is about hen's movements which means other hens don't move out the way and end up getting killed. Heart rate monitors will enable us to see whether stress might trigger smothering, or whether birds really are as calm as they appear when starting to smother one another. We will also measure other indications of a stressed flock and hen welfare: fearfulness toward humans and novel objects, stress hormones in the egg, faults in eggshells and bone injuries. It is important to understand smothering behaviour because it harms chickens welfare and causes deaths of 1.4% of birds in a flock die from smothering (this equates to 21% of all mortalities) and can kill more than 20% of hens in badly affected flocks. Whilst 1.4% overall may sound small, this equates to over 300,000 hens deaths and 86 million eggs lost across the UK egg farms. The real impact of smothering is probably much greater than this because often hens killed by smothering will not be recognised as such. In addition, the potential for injuries and stress in those that survive have never before been investigated. Our results will be used to understand what causes this behaviour which will help farmers know how to intervene to prevent smothering. Our results will be able to reveal if information in the BirdBox could provide a warning that smothering is imminent, or whether particular movements made by hens might be useful for early warnings of smothering. Through this project we will benefit by understanding the true impact of smothering for laying hen welfare.

不能有卵形农民想走进鸡舍，找到一堆死鸟，只是知道明天和第二天可能会再次发生同一事件，而无需阻止它。这是窒息的影响，这是一种奇怪的行为，母鸡彼此堆积，导致桩底部的鸡死亡。没有人真正理解鸡为什么这样做，而且通常它们似乎在窒息的情况下缓慢而平静地移动。自然，产生鸡蛋的农民希望减少这种行为，但是当他们在农场看着鸟类中时，这不会发生。它间歇性地发生，很难预测。因此，迫切需要新的方法来理解这种行为。在这些窒息的事件中，鸟类的行为和动机引起了科学家的极大兴趣，因为动物并不经常以如此平静的方式引起同一物种的其他动物的死亡。这项研究旨在调查何时，何时何地发生窒息，以及窒息对生存的鸡的影响。窒息的事实是不可预测的，这意味着需要大量农场来研究这种行为。与一家鸡蛋生产公司合作，我们将可以使用110群鸟类。这些都有一个监测系统，即鸟箱，记录了有关母鸡环境（例如通风和温度），食物和水的摄入量，鸡蛋产生以及母鸡死亡的数量和原因的信息。我们还将收集有关这些鸡在仍然是小鸡时是否受到压力的进一步信息，它们居住的谷仓的细节，什么时候发生窒息的事件以及在谷仓中发生的地方。所有这些信息都将被使用找到窒息的潜在原因，并查看是否可能有预警信号发生。尽管对于理解窒息行为的发展有用，但这些分析本身并不能确定导致鸡以窒息他人的方式移动的直接提示，或者实际上是什么动作引起了窒息。为了解决这个问题，我们将使用热摄像机和标准摄像机将心率监测器放在鸡和薄膜窒息事件上。热摄像机将使我们能够自动测量鸡的运动，从而能够对窒息进行逼真的模拟。窒息的模拟将使我们能够理解母鸡的运动是什么，这意味着其他母鸡不会走出去，最终被杀死。心率监测器将使我们能够看到压力是否会触发窒息，或者鸟类开始彼此窒息时是否真的像它们一样平静。我们还将衡量其他压力羊群和母鸡福利的迹象：对人类的恐惧和新物体，鸡蛋中的压力激素，蛋壳的断层和骨骼损伤。重要的是要了解窒息行为，因为它会损害鸡肉福利，并导致羊群死亡1.4％的鸟类死亡（这相当于所有死亡率的21％），并可能杀死受影响严重的鸡群中20％以上的母鸡。尽管总体上听起来很小1.4％，但在英国鸡蛋农场中损失了300,000多人死亡和8600万卵。窒息的真正影响可能比这更大，因为经常被窒息杀死的母鸡不会被认为是这样的。此外，从未研究过生存的人的伤害和压力的潜力。我们的结果将用于了解导致这种行为的原因将有助于农民知道如何进行干预以防止窒息。我们的结果将能够揭示小鸟箱中的信息是否可以警告迫使迫在眉睫，或者母鸡做出的特定动作是否可能对早期警告窒息有用。通过这个项目，我们将通过了解窒息的产生母鸡福利的真正影响来受益。

项目成果

Welfare epidemiology as a tool to assess the welfare impact of inherited defects on the pedigree dog population

福利流行病学作为评估遗传缺陷对纯种狗种群福利影响的工具

• 发表时间: 2010
• 期刊: Animal Welfare
• 影响因子: 1.2
• 作者: Collins L.M.

Extreme crowding in laying hens during a recurrent smothering outbreak

• DOI: 10.1002/vetr.245
• 发表时间: 2021-04-19
• 期刊: VETERINARY RECORD
• 影响因子: 2.2
• 作者: Herbert, George T.;Redfearn, William D.;Asher, Lucy
• 通讯作者: Asher, Lucy

Early locomotor activity in broilers and the relationship with body weight gain.

• DOI: 10.1016/j.psj.2022.102086
• 发表时间: 2022-10
• 期刊: POULTRY SCIENCE
• 影响因子: 4.4
• 作者: van der Sluis, Malou;Asher, Lucy;Rodenburg, T. Bas;de Haas, Yvette;de Klerk, Britt;Ellen, Esther D.
• 通讯作者: Ellen, Esther D.

Why Do Hens Pile? Hypothesizing the Causes and Consequences.

• DOI: 10.3389/fvets.2020.616836
• 发表时间: 2020
• 期刊: Frontiers in veterinary science
• 影响因子: 3.2
• 作者: Gray H;Davies R;Bright A;Rayner A;Asher L
• 通讯作者: Asher L

The effect of piling behavior on the production and mortality of free-range laying hens.

• DOI: 10.1016/j.psj.2023.102989
• 发表时间: 2023-10
• 期刊: POULTRY SCIENCE
• 影响因子: 4.4
• 作者: Armstrong, David;Asher, Lucy;Rayner, Ann;Ngidda, Halima;Sharma, Bryony;Gray, Helen
• 通讯作者: Gray, Helen