Behaviour, emotional expressions, stress and measures of brain function in relation to positive emotions in laying hens

There is increasing consensus that animal welfare is not only about the absence of suffering but the balance between positive and negative emotional states. There is, however, still no agreement on how to identify positive emotions in animals to detect po sitive welfare. In addition, some currently used stress indicators do not reliably distinguish between negative and positive experiences. The key questions are whether and under what circumstances animals experience positive emotions, and how these emotio ns are expressed behaviourally and physiologically. Briefly, the present study is designed to develop methods to ask hens how they feel, identify behavioural and physiological indicators that are associated with positive emotions, and to explore measures of brain functioning associated with positive emotions using pharmacological interventions. The principle objective is to adapt a model to assess positive emotions as a basis to measure, evaluate and improve welfare in laying hens. To achieve this, it wi ll be necessary to apply conditioning paradigms to describe behavioural and emotional expressions during anticipation of rewards differing in their rewarding properties, and positive rewards (access to sand and or worms) and negative rewards (aversive han dling) will be included. Effects of positive or negative emotional states on physiological indicators of stress will be investigated. To test the involvement of brain reward systems in association with anticipation of positive rewards, effects of positive anticipation on the opioid system will be investigated. Furthermore, in order to apply anticipatory behaviour as a tool for assessing welfare, effects of various degrees of environmental enrichment on behavioural and emotional expressions during anticipa tion of positive rewards will be studied. Our approach to study animal welfare is focused on signs of pleasure instead of post hoc signs of displeasure. Our team is interdisciplinary to achieve these goals.