Horses have evolved over time to be trickle feeders, consuming small amounts of forage throughout the day with no prolonged fasting periods. However, feeding some groups of horses free-choice hay can lead to problems such as obesity when the hay is too rich for them.

This has led to an increase in popularity of slow feeders to improve the management of horses. “When the primary forage source is too high in caloric density, the forage intake must be limited,” says Natalie Sullivan, MSc, equine nutritionist and owner of On Course Equine Nutrition, in Missoula, Montana. “A slow-feed device attempts to increase the number of hours the horse spends chewing and salivating to prevent unwanted behaviors and gastric ulcers.”

When to Use Slow Hay Feeders for Your Horse

It is no secret that there is an epidemic of equine obesity, which is a serious welfare concern for horses. When a horse needs restricted forage intake it can be challenging for owners to avoid prolonged fasting periods. Limited forage intake for horses can have serious consequences, such as an increased risk of gastrointestinal upset as well as the development of stereotypies—repetitive behaviors that have no apparent purpose. Therefore, owners should avoid fasting periods longer than four hours for their horses.

When some horses have free-choice access to hay, they develop excess adiposity (fat tissue) and become obese, which can cause an increased risk of metabolic disorders and health issues such as hyperinsulinemia-associated laminitis. Finding the right balance between forage access to prevent gastrointestinal issues and avoiding obesity is crucial to promoting good equine welfare.

Owners must exercise caution when restricting overweight horses’ forage intake: “1.5% of the horse’s body weight in forage is the absolute minimum required to prevent torsions, twists, and other gastrointestinal tract problems,” says Don Kapper, retired equine nutrition expert with more than 37 years of experience formulating products, researching, and teaching about equine nutrition.

When restricting your horse’s forage, Kapper suggests starting by splitting your horse’s daily hay ration into four meals, though some horses might need five or six meals if they finish their hay quickly. Dividing the rationed forage over many feedings within a 24-hour period can help avoid the horse having prolonged periods without access to hay.

How to Choose a Slow Hay Feeder for Your Horse

Again, slow-feeding devices can be extremely useful for making your horse’s hay last longer and help reduce the number of feedings. This might be especially helpful in a situation when four or more hay feedings are not practical.  

Owners have a variety of choices when shopping for a slow-feeding device. Some options include hay nets, hay balls, feeders made with plastic or metal grates, and automatic feeders. “I always provide clients with multiple options when recommending slow feeders,” says Sullivan. “I have found that there is not one that everyone tends to really like. Labor, cost of the product, and the horse’s personal preference are all factors that should be taken into consideration.”

If your horse needs a slow feeder to maintain a healthy body condition, it might take some trial and error to find a good fit. The ideal size of the feeding holes for your horse depends on his individual needs. If you are using a slow-feeding device, time how long it takes your horse to empty it. “There are horses that are more aggressive eaters than others,” says Kapper. “Even with the same amount of hay in the same hay net, horses will eat at different rates. Some situations warrant double-netting, which works, but note that it is very individual for what is best from horse to horse.”

Slow Hay Feeder Safety Considerations

Always prioritize safety when selecting and setting up a slow feeder for your horse. “Special precaution must be taken for horses with shoes,” says Kapper, for which he recommends products with smaller holes.

For shod horses, always hang hay nets at least one foot off the ground, Kapper adds. For horses without shoes, owners can make the net level with the ground, but the average hay net should never rest on the ground. “Everything needs a breakaway, like a leather strap, or even a piece of baling twine,” says Kapper, to ensure the horse can break free in the event of an emergency.

Sullivan says hanging hay nets too high can lead to poor respiratory health. “It is recommended that feeding lower to the ground, when safety allows, facilitates drainage from the nasal passage, which can lower the risk of respiratory infection,” she says.

“The majority of the time dental issues are not a concern, however, there are always exceptions,” says Kapper. “I have come across a hay net with plastic coated wire, and I would recommend staying away from those as that would increase susceptibility to dental and gum damage.”

Sullivan says she does not recommend slow feeders with metal grates for the same reason.

Hay Quality and Slow Feeders

When considering whether your horse can benefit from a slow feeder, carefully assess the quality of the hay. If you have an easy keeper, choose forage lower in caloric content so you won’t have to restrict forage intake as much. “When the primary forage matches the horse’s caloric needs, a slow-feeding device is not required,” says Sullivan. “If you are wanting to avoid hay waste when not using a slow-feeding device, simply use a product with larger holes (greater than 2 inches).”

If you have an easy keeper, having your hay tested can save you the frustration of restricting forage intake severely—knowing your hay’s caloric content and grade better equip you to make slow-feeding decisions. “Grades 3 and 4 hay are termed ‘utility hay’ and recommended for easy keepers,” says Kapper. “You can get hay that is so mature it can cause impaction colic. This would be Grade 5 hays,” which are not recommended for feeding.

When evaluating hay analysis results, look at the relative feed value (RVF), which can indicate the overall quality of that forage. Utility hay (Grades 3 and 4) is defined as having a RFV between 75 and 102, with higher quality forage being 103 or greater, and poorer quality forage falling below 74 RFV.

Therefore, if you have control over the hay your horse eats, focus on finding a hay source with a lower caloric content before choosing the best slow feeder for your horse. From there, use trial and error to find a slow-feeding method that works for your horse’s unique needs. Remember to prioritize safety and try multiple products if the first one isn’t a great match for you and your horse.