Despite the benefits of slow-feeding devices (SFDs), some ponies and horses may show signs of frustration when using these tools. Because SFDs are meant to improve animal welfare, primarily by extending feeding time, selecting an appropriate one that minimizes frustration is recommended.
SFDs include haynets, hay balls, and even a newer device called a hay box that sits on the floor with a haynet stretched across the top. These tools extend feeding time, which means it takes longer for a horse or pony to consume their meals, leaving them without forage for shorter periods of time during the day.
“One study showed that feeding time was extended by up to 61% compared to ground feeding by using a partially filled haynet. By extending feeding time, SFDs help mimic a horse’s natural foraging behavior, which improves stabled horse’s welfare. Further, the risk development of stereotypic behaviors such as wood chewing, cribbing, and stall walking may be reduced,” explained Catherine Whitehouse, M.S., a Kentucky Equine Research nutrition advisor.
She added, “Another benefit of SFDs is decreased hay wastage, which reduces feed-related costs.”
In addition, digestive disturbances such as gastric ulcers, particularly those affecting the squamous portion of the stomach, may be reduced by prolonging feeding times, as the stomach will not be empty for long periods.
“Ideally, horses should have ad libitum access to forage, but this is not always practical. Guidelines for minimizing time spent without access to forage have been suggested based on observations of naturally grazing horses, which tend to voluntarily fast for short periods of time, approximately three hours at a time,” stated Whitehouse.
Frustration behaviors have been observed when using SFDs. Examples include biting and shaking haynets, head pushing, pawing, ears backward or pinned, and even flinging the haynet.
To further assess frustration when SFDs are used, nine adult ponies were video recorded while feeding from a fully filled haynet, a partially filled haynet, a slow feeding box, and the ground. Those videos were evaluated by an individual trained in equine behavior.*
“Ponies fed from the ground showed the lowest rate of backward ears, a sign of frustration. The highest rate of backward ears was observed when feeding from haynets, particularly fully filled haynets. These findings corroborate other studies that also suggested backward ears were a sign of frustration when access to forage was restricted in some way,” Whitehouse said.
Blink rate was slower when feeding from the ground compared to the SFDs. While some studies suggest that horses and ponies have higher blink rates in stressful situations, this is not universally observed. This research team suggested that when the ponies in this study were feeding from SFDs, they may have been more focused and attentive, leading to a decreased blink rate.
None of the ponies showed any head pushing, striking with a forelimb, or pawing, which were observed in several previously published studies. In those studies, the horses would even fling and shake the haynet, presumably because it is not “easy” to obtain forage from the haynet when compared to feeding from the ground.
When manipulating forage intake rate, it is important to assess the horse’s adaptation and acceptance of the slow feeding device or grazing muzzle. Horse owners should be on the lookout for signs of frustration such as backward ear position, pawing or striking with forelimb, and head pushing to easily monitor their horses and modify their management practices.
For horses on a forage-based diet, be certain to offer supplemental vitamin E. While vitamin E levels are adequate in fresh pastures, dried or preserved forages such as hay have little vitamin E. Thus, horses with limited pasture access benefit from Nano-E, a natural-source, highly bioavailable form of vitamin E.
*Greppi, M., C. Bordin, F. Raspa, E. Maccone, P. Harris, A.D. Ellis, D. Bergero, and E. Valle. 2024. Feeding behaviour related to different feeding devices. Journal of Animal Physiology and Animal Nutrition (Berl):13977.
