Similarity in Temporal Movement Patterns in Laying Hens Increases with Time and Social Association.

Ariane Stratmann,Michael Jeffrey Toscano,Yamenah Gómez,Sabine Vögeli,John Berezowski,Bernhard Voelkl,Yandy Abreu Jorge,Sabine G. Gebhardt-Henrich

doi:10.3390/ani12050555

Abstract

Simple SummarySocial bonds are well-known to affect individual decisions or responses in specific situations, however, the impact of sociality on the individual activity behaviour of hens is largely unexplored. Therefore, we explored the relationship between social associations and individual daily movement patterns by studying the range use of domestic hens in a semi-commercial barn setting with automatic tracking of laying hens. We analysed the social relationships and the daily movement patterns of hens and found that hens were consistent in their individual variation in daily movement patterns and maintained stable social relationships. The social associations among hens correlated with movement patterns and this correlation increased with time, leading to more similar movement patterns of socially associated individuals. This study clearly shows that the social environment within a group can shape and enhance variation in movement patterns of individual animals.We explored the relationship between social associations and individual activity patterns in domestic hens. Out of 1420 laying hens, 421 hens were equipped with RFID tags attached to RFID-specific leg bands (leg bands from Company Roxan, Selkirk, Scotland) to continuously track their change in location across four different areas (one indoor and three outdoor areas). Using a combination of social network analysis for quantifying social relationships and dynamic time warping for characterizing the movement patterns of hens, we found that hens were consistent in their individual variation in temporal activity and maintained stable social relationships in terms of preferred association partners. In addition to being consistent, social associations correlated with movement patterns and this correlation strengthened over the period of observation, suggesting that the animals aligned their activity patterns with those of their social affiliates. These results demonstrate the importance of social relationships when considering the expression of individual behaviour. Notably, differences in temporal patterns emerge despite rather homogeneous rearing conditions, same environment, and low genetic diversity. Thus, while variation in behavioural phenotypes can be observed across isolated individuals, this study shows that the social environment within a group can shape and enhance variation in general movement patterns of individual animals.

Highlights

Social organization is a key aspect of animal ecology, closely interlinked with anatomical, morphological, physiological, and behavioural traits [1,2,3]
In order to create social networks, we identified dyadic associations defined as spatiotemporal co-occurrences of birds at the radio frequency identification (RFID) antennas fixed at the transition point between neighbouring areas
Comparing thecombined cluster categorization ofall hens and Comparing cluster categorization hens basedclustering on movement patterns and social associations, we found highthe correlations betweenofthe hens’

Summary

Introduction

Social organization is a key aspect of animal ecology, closely interlinked with anatomical, morphological, physiological, and behavioural traits [1,2,3]. If groups of animals are moving, group cohesion represents a permanent challenge as individuals have to coordinate their movements and more generally their activity patterns How this feat can be achieved has been studied under the umbrella term of collective behaviour [12,13]. The presence of many individuals in a small area can lead to various forms of competition—e.g., when individuals interfere with each other’s foraging activity [14]—or sometimes kleptoparasitism [15,16,17]. In such cases, composition, size and structure of the social group have direct consequences on the effectiveness of foraging activity. Under aversive conditions (e.g., food scarcity) which require increased foraging activity, baboons (Papio sp.) reduce resting time rather than social grooming time—the latter being an important mechanism for forming and maintaining social bonds [1,19]

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