Kentucky Humane Society Launches Fertility Vaccine Program for Eastern Kentucky Wild Horses

Effort aims to control growing population, reduce over-foraging and safety issues on rural roads

Mar. 13, 2026 at 9:49pm

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The Kentucky Humane Society is implementing a new fertility vaccine program to manage the growing population of once-domesticated horses that have been roaming free for decades in eastern Kentucky. The horses are over-foraging the land, threatening wildlife, and causing safety issues on rural roads. The vaccine program will dart mares twice in the first year and then annually to reduce the birth rate and control the herd size.

Why it matters

The wild horse population in eastern Kentucky has been straining the local environment, pushing out other wildlife like deer and elk, and creating dangerous situations on rural roads. The fertility vaccine program offers a proactive approach to managing the herd size and reducing the need for costly rescues and rehoming efforts.

The details

The horses are mixed-breed animals with unknown lineage, a far cry from the thoroughbreds and saddlebreds Kentucky is known for. They are over-foraging the land, leaving the landscape barren and pushing out other wildlife that local residents depend on. The new fertility vaccine program will dart mares twice in the first year and then once annually to reduce the birth rate and control the herd size, which is estimated to be around 1,000 horses currently. The vaccine program is expected to start impacting population numbers in 2027.

  • The Kentucky Humane Society has been working with this population of horses for about a decade.
  • The fertility vaccine program runs for three years, with mares being darted starting now.
  • The vaccine program is expected to start impacting population numbers in 2027.

The players

Kentucky Humane Society

A non-profit organization that is implementing the fertility vaccine program to manage the wild horse population in eastern Kentucky.

Lori Redmond

A representative from the Kentucky Humane Society who has been working with the wild horse population for about a decade.

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What they’re saying

“They're struggling on their own, and it's very different than the nice farms in Louisville and Lexington. And I saw the starving horses that were walking skeletons, and it had a very big impact on me.”

— Lori Redmond, Kentucky Humane Society (wtvq.com)

“It causes the deer and elk to struggle... and people want them to hunt, and people turn their cattle out, and that's their source of income.”

— Lori Redmond, Kentucky Humane Society (wtvq.com)

What’s next

The fertility vaccine program runs for three years, and mares being darted now will begin to impact population numbers starting in 2027.

The takeaway

The Kentucky Humane Society's fertility vaccine program offers a proactive solution to manage the growing wild horse population in eastern Kentucky, which has been straining the local environment and creating safety issues. By reducing the birth rate, the program aims to control the herd size and minimize the need for costly rescue and rehoming efforts.