Comparing behavioural sampling methods in shelter dogs: implications for enrichment studies

Animals living in human-dominated environments often face constrains on expression of natural behavioural repertoire and compromised welfare. Domestic dogs (Canis lupus familiaris) housed in shelters provide a valuable model for examining both welfare outcomes and methodological approaches to behavioural assessment in an artificial, and human organised, setting. Here we evaluate behavioural sampling methods within an ecologically valid experimental framework. Specifically, we compared continuous recording (CR) and instantaneous sampling (IS; 15s, 30s, and 6s intervals) following enrichment manipulation, reflecting a real-world research context for behavioural data collection. From a methodological perspective, results showed that IS systematically underestimated behavioural expression compared to CR, with increasing underestimation from IS-15 to IS-60. Regarding enrichment, using CR as the most reliable approach, we investigated the short-term behavioural effects of social interaction with conspecifics and food-based olfactory stimulation. We found that, while overall behavioural repertoires did not differ markedly between enrichment conditions, inactive lying increased following social interaction compared to olfactory enrichment. Stress-related behaviours were rare, indicating that neither enrichment type was aversive and that both social and olfactory enrichment can be safely implemented in shelters. Our findings highlight the importance of aligning sampling methods with specific research aims and behavioural outcomes and inform the implementation of different enrichment programs in shelter dogs. This integrated approach aligns with the principle of reduction by maximising information from a single dataset, allowing methodological and experimental conclusions under realistic conditions.