Tracking individual laying hens in group housing

Many animal species live in social groups and show complex social behaviour. Social behaviour has been well studied on various levels, ranging from classical ethological approaches, i.e. behavioural observations, to experimental and evolutionary approaches focussing on the fitness value of group living. Yet while research on smaller groups has provided important insights into behavioural mechanisms, such research on larger groups has been hampered by the inability to keep track of the movement and behaviour of individuals. For large populations, predominantly approaches have been taken that describe group or flock behaviour, for instance swarming behaviour in birds [1], schooling behaviour in fish [2] and social dynamics in humans [3], but those approaches usually do not allow linking individual characteristics to group behaviour. In smaller groups, an individual-based approach allows us to link the characteristics of a given individual to the behaviour of the group. However, challenges arise when these methods are applied to large groups of animals due to challenges associated with a larger number of animals interacting with each other and very different social dynamics.