In domestic condition, adult stallions are mostly housed in single box stables. Social deprivation in horses results in physiological stress and behavioural problems. This study aimed to test the “social box” (SB) allowing closer physical contact between neighbouring horses. Eight pairs of stallions (n=16) were filmed over a 24h period in the SB and in the “conventional box” (CB) strongly restricting tactile contact. The impact of the housing in the SB on behaviour and the occurrence of injuries was investigated. The total duration of active social interaction was significantly higher in the SB than in the CB (51.1 vs. 4.9 minutes, p<0.0001). Positive interaction accounted for about 71% of the total duration of interactions in both 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 24h, p<0.0001). No grievous injuries were recorded. The social box appears to be a suitable solution to give adult stallions the possibility to have physical interactions, and therefore be considered as a substantial environmental enrichment for horses housed in individual loose boxes.