Does Your Horse Need a Roommate?

Researchers compared stable types and stress hormones with an eye to equine welfare
Mares and foals at the Spanish Riding School’s stud farm at Piber, Austria. They come into what is effectively an indoor paddock at night.

People work in cubicles. Horses live in stalls. It’s the way of the world…isn’t it?

Maybe the age of the cubicle is over. Business magazines are full of articles about innovative work arrangements at companies like Google that offer employees flexible work spaces free of walls and boundaries. It’s supposed to encourage innovation and minimize stress.

Are horses so different? British researchers studied horses in different types of barns and measured their levels of a key stress hormone. They found that the more sociability a barn offered, the less stress hormone was measured.

But before you place an ad on CraigsList for your horse’s equine roommate, learn a bit more about this research project. 

The results of the study “Domesticated horses differ in their behavioral and physiological responses to isolated and group housing“ by Kelly Yarnell, Carol Hall, Chris Royle, and Susan L. Walker are published in the May 2015 edition of the Elsevier journal,Physiology & Behavior, and summarized here.

American readers may be unfamiliar with group barns, but they have been in use in Europe for a long time, and are in passive use here for horses that are “stabled” at pasture and use run-in sheds or have optional access to a barn. The Spanish Riding School’s stud farm at Piber uses group barns for mares and foals, with mares going into box stalls at foaling time.

The researchers at England’s Nottingham Trent University observed horses’ behavior in four types of housing designs – housed completely alone, kept individually but with a small amount of contact from neighboring horses, housed in pairs in a barn, and group housing in a paddock.

They found that as housing became more isolated, horses exhibited higher levels of fecal corticosterone, a key indicator of stress.

Thermal images of the eye, another non-invasive measure of stress response, showed eye temperature to be significantly lower for group-housed horses – showing lower levels of stress – when compared to all others.

Meanwhile, behavioral analysis showed horses became increasingly difficult to handle, the more restrictive and isolated the housing became. And horses kept in groups were more likely to exhibit natural behaviors typical of free-ranging horses, with a good standard of welfare, the team found.

During the study, horses were exposed to each housing design for five days and were turned out into grass paddocks for two days before exposure to the next design.

Fecal samples were collected for testing once a day for the first three days, while thermal images for temperature collection were captured three times a day. Behavioral observations were carried out on the final day for seven hours, using a remote camera system.

The study, which looked at 16 horses, was carried out by the University’s School of Animal, Rural and Environmental Sciences.

It’s interesting that the full social contact “housing” was actually an outdoor paddock. Indoor common barns do exist, but for the purposes of this research, the four types of stabling were defined this way:

  1. ‘Single housed, no contact’ – horses housed in box stables with solid brick walls to the rear and side. No contact with other horses possible.
  2. ‘Single housing, semi contact’ – horses individually housed in box stables with a solid wall to ceiling height at the rear. The front, sides and integrated sliding door included vertical metal bars allowing auditory and tactile communication with the neighboring horse at either side.
  3. ‘Paired housing, full contact’ – horses housed in pairs in a barn. The barn lay adjacent to indoor single box stables allowing the horses visual and auditory contact with the horses stabled in them. In addition, there were two horses in the neighboring barn allowing for visual and auditory contact through a wire partition separating the two enclosures. Each pair of horses had full physical contact with another.
  4. ‘Group housing, full contact’ – horses were turned out in their experimental group of four into a paddock which had been grazed bare prior to the study. The horses had full physical contact with each other and visual and auditory contact with horses in nearby paddocks.
Are the barns we love the same ones that horses love? (Flickr photo by Andy, location unknown)

Dr Kelly Yarnell, an expert in equine welfare at Nottingham Trent University offered these comments:

“Inadequate housing design potentially causes stress and negative consequences on the health and wellbeing of horses – despite the fact it can be easily addressed by introducing more windows or shared areas, for instance.

“To the human eye, the stable appears safe and inviting and is based on the belief of what the horse finds comfortable. However, for a social animal that spends most of its time in close contact with other horses, the isolation brought about by single housing could activate an equine stress response.

“Group housing provides horses with an environment where they are able to display natural behavior, and contact with other horses improves overall welfare.”

The final sentence in the paper’s summary deserves notice: “These results indicate that, based on physiological and behavioral measures, incorporating social contact into the housing design of domestic horses could improve the standard of domestic equine welfare.”

The discussion section of the paper brings up many interesting factors that affected the study. In addition, many horse owners would protest that by separating horses we are facilitating horse welfare by insuring that all horses have access to clean bedding, water, and feed without competition and stress from peers. Obviously, the group that is housed together has to be a friendly group. Many of us spend a lot of time and energy figuring out which horses are suitable to be turned out together, based on personalities.

Horses that have access to all-day turnout will have different energy and personality triggers than horses that have only short periods outside their stalls. It’s important to note that the horses in this study were riding school horses that were enjoying a month off during the summer, and had no work by students during the test period.

In the paired and group stabling models, we can all envision the bonding that would take place, and the inevitable separation anxiety that might result when a single horse is taken out for exercise and the other left in the stall. That’s certainly a form of stress, too. On the other hand, if horses are living outside all day and just coming in at night for stabling, that wouldn’t be as much of a problem, although some horses do become very attached to their herd. The researchers even studied how much time the horses spent lying down and what types of playful or hostile behavior they displayed, and whether or not they engaged in any type of mutual grooming or stereotypical behavior like cribbing.

Should you rip the stall walls out of your barn? Everyone observes their horses and when one shows stress or strange behavior, it is sometimes surprising how changing that horse to a different stall with a different sight line or neighbors can change that horse’s demeanor. This study is a natural extension of those types of results. More sight, more sound and more air circulation never hurt any barn…and the horses usually appreciate the change.

Follow this link to read the full paper:

See more publications by Dr Kelly Yarnell:




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