I've talked before about how clicker training motivates horses, which brings up the issue of feeding treats to horses in general. It's a controversial topic. I'll never forget asking the late, great horseman Tom Dorrance ("grandfather" of natural horsemanship) if it was ever OK to feed treats. That was for a Q&A in Horse & Rider circa about 1997. His characteristic reply: "It depends."
He went on to explain that careless feeding would almost certainly result in nipping, but that if you always required good manners from the horse in accepting the treat, and never rewarded "demanding" behavior, then you might be able to do it with good effect.
Another wise horseman, Robert M. Miller, DVM, was equally circumspect when I asked him the same question in 2009. "The use of food rewards," he said, "requires expertise and experience." The popular author and originator of imprint training for foals went on to share his own safety strategy in using food rewards--teaching a horse to turn his nose away from him before he gives him the treat.
Stacy Westfall, whose success in bareback/bridleless reining once landed her on the Ellen DeGeneres show, says she never feeds treats to 2-year-olds, or to any horse whose groundwork isn't already well established. She also never lets a horse "strip search" her for a treat. She does, however, feed peppermints as a general mood-enhancer for her performance horses.
"It helps them think there's more to life than work all the time, and encourages them to have a happy feeling about me," she explains. But, again, she cautions that care is needed to avoid spoiling a horse with treats.
LEARN MORE about what these experts and others say about using food and other rewards to train your horse: "Reward Your Horse the Right Way."