For the first time in 44 years, I witnessed adult horses eating their manure. I am certain that these horses were doing it due to boredom. They were horses that came in from a large pasture, to be stalled with a run. Within a month they started eating about 50% of their piles. Being a Vet. Tech. I knew about Forbid for dogs and cats. Someone told me that it has been used on horses. I ordered it and it does work. This vise is also learned. My horse who never did this, started doing it. I treated her for only 2 days. She stopped, but started back up a week later. I treated her 5 days, and she stopped. Completely. All the horses ate it with no problem.