Fire officials estimated losses at $500,000 but said they expected the figure to rise.
The fire started about 3:30 a.m. and quickly swept through the barn at Cross International, a boarding and training facility. The cause of the fire was unknown.
Fire chief Bill Shaw said the barn's roof had already collapsed by the time the first firefighters arrived.
Eighteen horses died inside the barn, Shaw said. Four escaped, but had to be euthanized because of the severity of their injuries.
Mark Bowling, an owner of the property, declined comment due to the pending investigation.
Kentucky State Police arson investigator Damon Fleming said officials must wait until the remains of the building cool to determine how the fire started.
Trainer Steve La Rue told The Gleaner newspaper that the 12 thoroughbreds and three quarterhorses he lost ``were like our kids.''
``It doesn't get any worse than this in this business,'' La Rue said.
