Steps into a Small World: First glimpses on everyday moment-to-moment decision making in an ecologically meaningful multi-choice system for assessing animal preferences

The behaviour shown by an animal at any one time is the consolidated output of its behavioural control mechanism. Moreover, what animals “want” is viewed as (the most) important component for individual welfare. Accordingly, studying the motivation of animals helps understanding basic mechanisms and welfare related needs. However, studying wants of animals is notoriously difficult and many previous studies on the preferences of animals have been restricted in the sense that only two choice options were presented in an artificial test environment. Here, an extended approach, the “Small World” is presented, in which the choices of animals between eight ecologically relevant resources can be observed in a long-term test to reach conclusions with respect to everyday moment-to-moment decisions. In this sense, the system offers a quasi-natural environment. The approach was tested in three experiments with observations of individual female rats, small groups of female rats (Long Evans, Rattus norvegicus) and small groups of female chickens (Lohmann Brown, Gallus gallus domesticus). The animals oriented themselves quickly in the system and it was possible to collect multifaceted data on the use of the resources. These data included the faecal and urinary markings in the Small World cages, the daily frequency and duration of visits to these cages, the sequential analyses of the choices for and decisions among the resources, and the synchrony of the animals in the groups. Given the richness of these data and the lack of a stress response in the tested animals, the use of the Small World approach seems to be highly promising as an extension to previously used procedures. To further improve the approach and more directly reflect the subjective value of the different resources from the animals' point of view, the distances between the resources in a quasi-natural landscape shall be manipulated in future studies.