Housing stallions has, traditionally, not been very welfare-friendly, said Silvana Popescu, PhD, of the University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, in Romania. Her group’s work has revealed that, often because of a lack of personnel or staff training, stallions end up enclosed in box stalls or, worse, tied in stables nearly 24 hours a day. Some stallions never get more exercise than the walk to and from the breeding shed and the breeding or semen collection act itself. Many never get any physical access to other horses—male or female.

These deprivations can have serious consequences on the horse’s mental, physical, and emotional states, said Popescu. “Considering them highly dangerous among each other in all situations makes people almost forget that they are equines, part of their own species and having the same basic needs as the other categories of horses (foals, youngsters, geldings, and mares),” she explained.

The Misunderstood Sex

Stallions sometimes generate fear in handlers, which is a sort of prejudice, says Mathilde Valenchon, PhD, senior research associate at the University of Bristol in the U.K. “Are stallions intrinsically high-strung and dangerous, or have we conditioned them to become so through the way we manage them from their earliest years?” she asked. “Our management of them—treating them as scary and dangerous and always separating them—could be making them scary and dangerous.”

Popescu agrees. “Our primary mistake in housing stallions is actually in our perception of stallions itself, which lies at the base of our management decisions,” she said. “Because of this perception, people can have a very deep-rooted rejection of certain management practices (like group life in pastures) that we readily accept for other horses. This type of thinking is so well-established that people tend to have a ‘yes, but’ reaction when faced with examples showing that things can be the other way around.”

Getting Them Outdoors

Stallions need outdoor free time, these sources agree, which is one of the “Five Domains” of freedoms for all animals as defined by the World Organisation for Animal Health (OIE).

Swiss researchers have successfully kept stallions in groups outdoors, with about eight stallions living together and creating “bachelor groups,” said Sabrina Briefer Freymond, DVM, PhD, of the Agroscope Swiss National Stud, in Avenches, Switzerland. While this is possible, it requires significant precautions such as keeping all other horses—especially mares—out of viewing, hearing, and smelling distance and only allowing group pasturing outside of the breeding season. Equine behavior experts must oversee the project to ensure the stallions get along well to prevent injuries, she said.

This utopic stallion housing situation isn’t possible for most studs, however, said Christine Aurich, DVM, PhD, head of the Graf Lehndorff Institute for Equine Science, in Neustadt, Germany. One slight management mistake could lead to serious and even fatal injuries between fighting stallions.

Instead, stallions can benefit from safe outdoor pasture time in individual paddocks, she said. “Stallions should at least see other horses, and they have to get access to pastures or paddocks, but the fences have to be very strong,” said Aurich. “It is also better when there are no estrous mares walked along these pastures.”

Safe Contact With Other Horses

Stallions can have safe social contact if handlers plan for it properly. If they live in groups, under the auspices of very well-trained behavior experts, they need large pastures with plenty of space to get away from other stallions without feeling “trapped,” said Aurich.

This is also true in box stalls, she said. While it might seem like stallions are safe if housed in rows with strong walls dividing them from other stallions, the horses themselves don’t necessarily perceive it that way. Her team’s research revealed that cortisol (stress hormone) levels were higher when stallions lived in individual box stalls than in groups—and not just because they were isolated or being used for semen collection.

“This increase is much more likely caused by aggression among stallions,” said Aurich. “If the stallions are kept in boxes, they cannot escape this threat, but it is possible if they are kept in a group.”

One solution for stalled stallions could be giving them an “escape,” she said. “This could be done by having large boxes and giving them some ‘privacy’ with part of the partition wall being solid and only parts of it built with grids that allow for visual and also tactile (nose-to-nose) contact,” Aurich explained.

At the Swiss National Stud in Avenches, Anja Zollinger, BSc, and her fellow researchers have developed a “social box” for stallions, which allows far more than nose-to-nose contact. By selecting stallions that get along with each other and only permitting social contact between two stallions (not open contact across all box stalls), they have allowed breeding stallions to have head-to-toe contact with each other through full-vertical openings. The 15-inch openings are wide enough to let legs pass through, but not the body. Critically, there’s a fully closed wall area, as well, where a stallion can retreat and take a break from the contact as needed, Zollinger said.

Friends and Rivals

An essential part of stallion housing involves stallion observation, researchers agree. Stallions create clear affinities for certain stallions and can have extreme distaste for others—for reasons humans might never know. It’s up to handlers to recognize and respect those preferences in their management.

“We keep our research Shetland stallions in groups, but even this is a constant challenge,” Aurich said. “There are always individuals that do not like each other. So you have to keep an eye on them all the time and regroup the animals if necessary. Some stallions will not accept any other stallion at all.”

Some working horse breeders in Popescu’s home country of Romania have long housed stallions together if the conditions are right—including that the stallions like each other.

“The key element was always considered the individual behavior of certain stallions,” she said. “One can manage and keep stallions together with a certain temperament, character, and behavior, but that doesn’t apply to just any stallion. The accent was always on the innate mental traits of the animal, rather than on the people’s possibilities to intervene.”

This aligns with Aurich’s experience, as well. “If they really hate each other and fight all the time, this should be avoided,” she said. “It’s very interesting how horses like or dislike their companions. It certainly takes time and a lot of behavior observation to find good matches.”

Take-Home Message

Stallions have equid-specific ethological needs just like any other horse. As research continues to enrich our knowledge about healthy and welfare-friendly housing for horses, we can’t exclude intact males from the benefits of that knowledge, these researchers say. Using caution, good sense, and excellent observational skills, handlers can develop better housing methods for these too-often-feared horses that provide them freedoms without sacrificing their safety.