Study adds evidence for mixed group housing of stallions, geldings
Bottom line
A new equine welfare study in Veterinary Sciences reports that stallions and geldings can be kept together in group housing without higher movement demands or observed injuries, at least under the conditions studied. Researchers Rhoda C. Apitzsch, Sarah Händel, and Konstanze Krueger observed 35 horses in four mixed groups in Germany from July to September 2024, including 18 stallions and 17 geldings, and tracked their behavior and movement over three consecutive days. Published July 7, 2026, the study found that stallions showed more affiliative, agonistic, dominance, ritualized, reproductive, and play behaviors than geldings, while attack, threat, avoidance, resting behavior, and overall movement activity did not differ significantly. No injuries or stereotypic behaviors were observed during the observation period. (staging.core.mdpi.com)
Why it matters: For veterinary professionals advising barns, breeders, and pet parents involved in equine care, the findings add to a growing body of evidence that intact males don't necessarily have to be managed in social isolation. Earlier reviews and housing studies have linked solitary stallion management with more undesirable behaviors, while also emphasizing that successful group housing depends on practical conditions such as stable group composition, adequate space, careful acclimation, and limited mare contact. In the new study, greater space availability per horse was associated with more comfort, resting, reproductive, and play behaviors, while dominance behavior decreased and attacks tended to decline as space increased, reinforcing that facility design may matter as much as sex status. (staging.core.mdpi.com)
What to watch: Whether these findings influence welfare guidance or barn management practices will likely depend on follow-up studies in larger populations, different housing setups, and longer observation periods. (staging.core.mdpi.com)
A study published July 7, 2026, in Veterinary Sciences adds fresh data to a longstanding equine welfare debate: whether stallions and geldings can safely live together in group housing. In four mixed groups in Germany, researchers observed 35 horses, including 18 stallions and 17 geldings, and found no injuries or stereotypic behaviors during the study period. Stallions were behaviorally more socially active than geldings in several categories, but they did not travel farther and did not show significantly different attack, threat, avoidance, resting, or overall movement activity. (staging.core.mdpi.com)
That matters because stallions are still often managed more restrictively than other horses, largely out of concern about aggression, injury risk, and breeding management. Earlier literature reviews have described group housing for stallions as feasible in principle, with potential welfare benefits when management is right, but uptake has remained limited. One review cited surveys from Germany showing relatively low use of group housing for stallions, alongside higher rates of undesirable behavior in animals kept mostly alone. (mdpi.com)
The new study focused on behavior and GPS-measured movement in mixed-sex-status male groups housed in Germany between July and September 2024. Horses were observed for three consecutive days over eight hours per day. The authors reported that stallions showed significantly higher levels of affiliative, agonistic, dominance, ritualized, reproductive, and play behaviors than geldings. At the same time, there were no significant differences in attack, threat, comfort, avoidance, resting behavior, or movement activity, and the horses moved an average of 2.36 kilometers during the observation periods. (staging.core.mdpi.com)
One of the more practical findings was the apparent role of space. The study found that greater space availability per horse was associated with increased comfort, resting, reproductive, and play behaviors. Dominance behavior decreased as space increased, and attacks also tended to decrease. That aligns with prior stallion housing research suggesting that social management works best when horses have enough room, stable group composition, and the ability to avoid conflict. A 2023 study of “social box” housing for stallions similarly emphasized that limited contact and isolation can contribute to welfare problems, while direct social interaction supports wellbeing. (staging.core.mdpi.com)
The broader research backdrop points in the same direction, though not always with a simple “group housing is always better” conclusion. A 2021 review in Animals concluded that group housing of stallions is possible and can positively affect behavior, but also noted that some horses may need alternatives, especially after prolonged isolation or in high-turnover settings. More recent work in sport horses has also reinforced the importance of forage, freedom of movement, and tactile social interaction as core welfare fundamentals. (mdpi.com)
Why it matters: For veterinarians, this study offers a more nuanced evidence base for conversations with breeders, trainers, boarding facilities, and pet parents. The takeaway isn't that every stallion should immediately be turned out in a mixed male group. It's that stallion status alone may be a poor proxy for welfare risk. Housing design, available space, social experience, group stability, and daily management appear central to whether group systems succeed. That has implications for preventive behavior counseling, welfare audits, injury-risk discussions, and recommendations around castration as a management tool. (staging.core.mdpi.com)
For practices serving equine clients, the study may also help reframe how behavioral complaints are interpreted. If stallions in well-designed group settings can show more ritualized and affiliative behavior without more attacks or injuries, some behaviors commonly viewed as inherently problematic may instead reflect normal social expression. That distinction matters when advising on housing changes, enrichment, and risk mitigation, especially as welfare expectations continue to rise across the horse industry. (staging.core.mdpi.com)
What to watch: The next step is whether larger and longer-term studies confirm these findings across different breeds, seasons, facility layouts, and management systems, and whether welfare bodies or equine organizations begin using that evidence to update practical guidance on stallion housing. (staging.core.mdpi.com)