Mary Hartman didn’t intend to be a pioneer in the horse feed industry; it just worked out that way, and it all began out of love for a horse.
‘I think there are quite a few people in the horse industry who create a company because of their equines,” Hartman contends. “I had a need, and what I needed was not available in the market, so I made it.”
Hartman founded StableFeed in 2017 in Kasson, Minnesota, producing feed and supplements that use innovative ingredients to support horses’ systemic health. StableFeed products use ingredients such as sainfoin, timothy hay, carrots, and berries. Sainfoin is a highly palatable, non-bloating perennial legume used for forage, hay, and even honey production. Sainfoin also offers environmental advantages. As a cover crop, it only needs tilling every 20-30 years, while early research indicates that sainfoin as a feed may reduce methane emissions from cows and other animals.
Hartman recognized that existing processed feeds weren’t meeting the needs of horses, so she set out to do something about it. She worked on some formulations in her kitchen before connecting with AURI.
“I started working with AURI to create a feed product based on food and bioavailable ingredients for the horse,” Hartman says.
Hartman says StableFeed’s progression went from a sick horse to a kitchen-made supplement to the point where she needed to move into a larger production and shipping facility.
“We grew from a kitchen business to this year, where we anticipate selling $2 million in products,” Hartman says.
StableFeed now offers nine sainfoin and three chia supplement products, which are distributed nationwide. Hartman was recently contacted about expanding her products into South America.
Building an Industry
Beyond producing horse feed and supplements, Hartman is building a market for sainfoin. The crop production needed to supply StableFeed demand has expanded from about 80 acres in 2021 to more than 2,300 acres under cultivation in 2026.
“I also worked with AURI to look at sainfoin,” Hartman explains. “Sainfoin is a really great forage, so I started working with AURI to come up with a feed. At the same time, I started looking for people to grow sainfoin because it pretty much disappeared from the U.S. For the past three and a half years, we’ve been growing our sainfoin supply and growing that market into the United States. That’s really been the progression. Now we’re in the growth phase and looking for ways to scale.”
“One of the goals that AURI has for projects that we begin to work with is to see them grow and get to that stage of large-scale commercialization and product distribution,” notes AURI Senior Scientist for Coproducts Alan Doering. “Mary’s there, and she continues to expand.”
AURI recently recognized StableFeed by selecting it as the organization’s 2025 Ag Innovator of the Year.
The Ag Innovator award recognizes an AURI client that has shown innovation in their product or process, has utilized AURI’s technical services, uses substantial quantities of Minnesota-grown commodities, and has achieved a level of market success.
Doering says StableFeed is a shining example of what the award seeks to recognize.
“StableFeed is not only growing but continuing to innovate. We’re excited to work with them on the next big thing they pursue,” Doering adds.
Hartman says she got into the feed business for a horse, and she’s still in it for a horse, although it’s no longer exclusive for the ones she owns.
“Almost every day of the week, we get a phone call or a message from somebody telling us how the work we’ve done here has saved their horse,” Hartman observes. “That is the single most rewarding thing, and that is what keeps us going.”