Introducing a New Horse to the Herd

Last Updated on February 23, 2022 by Allison Price

Here are some ways to lower the risk of introducing horses to established herds.

It’s likely that you’ll never forget the sight of an unknown horse trying to get into an established herd. It can be quite frightening to see the violence displayed by the herd members in their pursuit of the newcomer. This is a normal behavior and, if you pay attention to the whys of herd dynamics when managing introductions, shouldn’t cause any more than temporary disruption.

Stability is what we are looking for

Horses have always been commodities and competitors. In today’s mobile society, horses are often accompanied with us as we move around, expecting them to adapt to new environments with ease. Horses place a lot of trust in their “home territory” and herds. Imagine what it would feel for a horse to be thrown from his stable, with its food and shelter, only to find that he is being chased by hungry carnivores or a group of venom-spitting horse riders just beyond the fence.

The change does not affect only the outsider. In the weeks that follow the introduction of a new member to the herd, other horses will have to restructure their hierarchy to allow for the stranger. The momentary uncertainty in social ranks may provide an opportunity for an ambitious young horse or a time when they are able to challenge the system. However, it can also be a stressful time where normally docile horses fight hard to preserve their social rank. The risk of injury increases dramatically, and the chaos can be very stressful.

Horses can be affected by stress, just like people. Mobile horses are more at risk for both viral and bacterial disease. A new horse might carry a disease that the horses are not immune to, or they might be infected by the environment or members of the herd.

Gender Factor

The introduction of a new horse gender, the gelding, is one of the most obvious effects of domestication. Katherine Houpt (VMD, PhD), says domestic herds that contain a mixture of mares and geldings can faithfully mimic the instinctive sexual behaviors and displays seen in wild herds. Houpt says that sex is not a major issue in the daily life of feral horses. Houpt explains that all horses in the wild are neutralized by the fact most mares are pregnant.Mares may threaten each other to establish dominance but usually stay relatively calm.

Unbred domestic mares can spend much of the year in estrus and, in mixed-gender herds sexual pressures could increase an established group’s hostility towards outsiders. Houpt states that many geldings do not realize they are geldings. Houpt says that the main problem isn’t that they show sexual behavior, but that they are aggressive towards other males. A new gelding that exhibits stallion-like behavior after being introduced to a herd may be rejected.

Then there is the concern about the potential dangers these stallion-like fights pose to bystanders and battlers.

A sexually aggressive gelding should be kept with other geldings, and away from mares, for the benefit of the whole herd. Cynthia McCall, PhD says that geldings’ sexual behavior can be both learned and innate. “If a mare is gelded too late, for example after four to five years, she might mount mares, herd mares, or fight other geldings.”

Single-gender herds may have aggression. Although mares can threaten one another to assert dominance, they are usually calm and peaceful. Even though they can play rough with the mares, the Geldings are usually not a danger to one another. One quiet gelding can be kept together with a group of mares if necessary. A stallion can also be kept among mares with the obvious consequences.

The Cost of Confinement

Their wild ancestors could roam vast lands, but domestic horses can only live in a small area. Although their nutritional needs to roam are less as there is more food available, they still have a mental need. Horses need freedom of movement to be healthy and happy. Entrapment in small spaces can cause fear and may lead to injury.

Introducing a New Horse to the Herd

The increase in aggression between herd members is a result of confinement. This can also lead to a higher level anxiety and fear within the group. Overcrowded environments can lead to bickering and even violence, with members fighting over who gets what. As there is no escape from aggression, introducing newcomers into herds that are kept in tight spaces can lead to injury.

Constrictions can also lead to health problems. Too-close proximity to other people increases the likelihood of parasite infestation. Slipshod management increases the number of horses per annum, which in turn leads to a higher concentration of parasite eggs or larvae in paddocks and pastures. The “clean” horse will suffer if it is introduced to a parasitized herd. Conversely, the heavily infested horse who takes up residence in a tightly confined, but clean, operation is more likely to infest others.

The Social Graces

Weanlings often have to be separated from their domestic horses before they can learn socialization skills. Colts in the wild can stay with their herd for three years before moving on to form bachelor herds. The bachelor herd members live together as a roughhouse to practice for the fights to take horses from the established herds. The two-year-old fillies are allowed to leave the herd at around two years old, in order to avoid inbreeding. They eventually join other established herds, or are paired with bachelor stallions. Young feral horses are trained in the operations of herd society for two to three years before reaching maturity.In the wild, colts stay in the herd for up to three years before leaving to form “bachelor herds.”

These important learning opportunities are often denied to domestic children, however. A weanling may not be able to learn from his herd at the age of four to six months. Horses who spend most of their time in stalls or out on their own can have socialization issues.

Buttermilk was an ex-racehorse that lost several homes due to his cruelty to horses when he was put out to pasture. He spent his entire time in his stall trying to attack his neighbours. He was anxious about his neighbors, even when he was alone. His last owner “fed” Buttermilk another horse, but he was still determined to get Buttermilk to be nice. Buttermilk drove his pasturemate across the field for approximately a week, peppering him in bite marks. Buttermilk and his horse became more familiar with each other, until Buttermilk was “chasing the other horse” at the walk. They became friends and were eventually able to ride together with the larger group. Buttermilk became a socialized man three months later. He was still the herd drill sergeant and occasionally drove the other horses around the pasture in mass gallops.

Advance preparation

It is almost certain that any newcomer will be subject to a hazing period before they are allowed to join an established group. You can reduce the dangers by taking precautions before any new horses are introduced. Although quarantining a horse after it is born is the best way to control disease, it may not be practical in all situations. For effective quarantine, the horse must be kept separate from other horses. They should also be under different care for several weeks. These preparations can reduce injury and health risks.

  • Learn about the dynamics of your herd. You can learn about the personality and hierarchy of your horses to predict which ones will be most aggressive and who will be quiet. Houpt says that aggression during introductions will be mainly caused by lower-rung horses who are trying to climb the social ladder.
  • You will need to adjust your management style to accommodate the newcomer. If everyone wants to live comfortably in a shelter, shed-kept herds need plenty of space. Place the buckets and hay piles 20 feet apart if you are feeding horses out in the field. Let the dominant horse choose her feeding spot.
  • You can remove the hind shoes of aggressive horses from your new horse and keep them there until things calm down.
  • To locate and care for horses that are running or flustered, take a walk around the pasture. Dead or low-hanging branches, holes, protruding nail heads, and splintered boards can all be dangerous. However, even though your horses are used to giving a wide berth for the disk harrow, they might not be as attentive if a newcomer is scared.
  • If horses are being terrorized or trapped in dead-end spaces or sheds, you should block them off and create an escape route for him.

The formal introduction

After all the preparations, finally, the new horse arrives. Assuming the stranger is not ill for his journeys, and that the management and environment have been “vetted” and fixed, it’s now time to focus on the prevention of aggression between old and new.

  • The new horse should be kept in a neighboring paddock for at most two to three days, so they can have contact but not run if threatened. The fence that separates the paddocks must be strong and secure (no hoof-snaring wire or anything else) to prevent horses from coming in contact with the fence.
  • To ensure that they can bond, bring a nonaggressive middle-ranking horse with you to the new horse.
  • As much as possible, let the horse learn the layout of the pasture by himself or with his friend. After he is familiar with the area, he will be less likely to try to escape aggression or run into danger.
  • You can make the big introduction in daylight when your horse is able to see. If things get out of control, you can stay on the sidelines for several hours and watch the horse. If the temperature is high or the footing is slippery from mud, ice or is too cold, you should not rush.
  • The newcomer should be released at least 15 to 20 mins after being fed. This will ensure that there are no food fights, and the majority of the herd members will be grazing or resting. You’ll find them more relaxed and less likely to run around after feeding.
  • Horses should stop running if they feel tired or sweaty. If they don’t, it could be that an inner animosity is driving the horses’ aggression. You may have to take the horse out for the sake of everyone.
  • Take a few weeks to be attentive to all herd members. Check for any bites, bruises or lamenesses. Sniffles, sniffles, dull hair, lethargy, and other signs that could indicate illness or injury.
Allison Price
Allison Price

I’m Allison, born and raised in San Diego California, the earliest memory I have with horses was at my grandfather’s farm. I used to sit at the stable as a kid and hang out with my Papa while he was training the horses. When I was invited to watch a horse riding competition, I got so fascinated with riding!