Assessing the consequences of behavioural deprivation in laying hens

动物福利方面的一些最困难的问题与测量和解释行为限制的影响有关，当动物被关在圈养环境中时，行为限制会阻止它们表现出物种典型的行为模式。 “行为需要”一词通常用于指对动物表现可能很重要的特定行为模式，当被阻止时，会导致沮丧或一些负面的情绪状态，这些情绪状态会导致痛苦和损害福利。传统的蛋鸡饲养方式（电池笼）受到了高度批评，因为缺乏必要的环境资源来适应可能对母鸡福利很重要的基本行为活动。两种特别令人关注的行为活动是筑巢和洗尘;在没有适当刺激的情况下，在铁丝笼中观察到这两种行为的要素。产蛋前的母鸡有很高的动机去接近巢箱，并表现出行为反应，当巢箱不可用时，这些反应被认为是沮丧的迹象。尽管大量的筑巢和dustbathing动机的工作，有很少的尝试，在调查的情绪状态时，蛋鸡被剥夺或提供执行它们的机会。一些负面情绪状态的确凿生理证据将强化在没有巢箱或基质的情况下母鸡福利下降的论点。越来越多的人认为，动物的幸福感也包括体验积极情绪状态的潜力。 非人类动物情绪的大多数概念框架包括认知，神经生理和行为组成部分的方面，用于研究它们的几种方法可以应用于蛋鸡的研究。在这个项目中，将进行一系列实验，使用应激反应的措施，减少恐惧和痛苦的药理学试剂和被认为表明动物积极和消极精神状态的行为测试，以调查蛋鸡消极或积极情绪状态的证据，这些母鸡被拒绝或被提供机会从事筑巢和洗尘行为。

Some of the most difficult issues concerning animal welfare have to do with measuring and interpreting the effects of behavioural restriction that occurs when animals are kept in captive environments that prevent them from performing species-typical behaviour patterns. The term 'behavioural need' is often used to refer to specific behaviour patterns that may be important for animals to perform and that, when prevented, result in frustration or some negative emotional state that can cause suffering and impair welfare. Conventional housing of laying hens (battery cages) is highly criticized because of the lack of environmental resources necessary to accommodate basic behavioural activities that may be important for the welfare of hens. Two behavioural activities of particular concern are nesting and dustbathing; elements of both of these behaviours are observed in wire cages in the absence of appropriate stimuli. Pre-laying hens are highly motivated to access a nest box and show behavioural responses that are considered to be a sign of frustration when a nest box is not available. Despite the substantial body of work on nesting and dustbathing motivation, there have been few attempts at investigating the emotional states experienced by laying hens when deprived of or provided the opportunities to perform them. Corroborating physiological evidence of some negative emotional state would strengthen the arguments for reduced hen welfare in the absence of nest boxes or substrate. Increasingly, it is suggested that animal well-being also includes the potential for experiencing positive emotional states. Most conceptual frameworks for emotions in non-human animals include aspects of cognitive, neurophysiological and behavioural components and several of the approaches used to study them could be applied to the study of laying hens. In this project series of experiments will be conducted using measures of stress response, pharmacological agents that reduce fear and distress and behavioural tests thought to indicate positive and negative mental states in animals in order to investigate evidence for negative or positive emotional states in laying hens that are either denied or provided opportunities to engage in nesting and dustbathing behaviour.