Social Box: A New Housing System Increases Social Interactions among Stallions

In domestic conditions, adult stallions are mostly housed individually in internal stables to reduce the risk of injuries during social interactions. Social deprivation in horses results in physiological stress and behavioural problems. The aim of this study was to test the "social box" (SB), which allows closer physical contact between neighbouring horses. Eight pairs of stallions (n = 16) were filmed over a 24 h period in the SB and in their usual box stables, "conventional boxes" (CB), which strongly restrict tactile contact. The effect of housing in the SB on behaviour and the occurrence and characteristics of injuries was investigated. The total duration of active social interactions was significantly higher in the SB than in the CB (51.1 vs. 4.9 min, p < 0.0001). Positive interactions accounted for about 71% of the total duration of interactions in SB and CB stabling. The stallions interacted significantly more often in the SB than in the CB (113.5 vs. 23.8 social interaction sequences over 24 h, p < 0.0001). No grievous injuries were recorded. The social box appears to be a suitable solution to give adult stallions the possibility of having physical interactions. Therefore, it can be considered a substantial environmental enrichment for singly housed horses.