Caroline Sather, 9, sat in an office chair Friday, swinging her legs as she tried to explain how a horse successfully clears a jump. “It’s the shape of the horse,” she said. “And where they lifted off ...

In the equestrian world, those sizes make a big difference in competition and in the animal’s value. By Sarah Maslin Nir Reporting from the arena known as Pony Island at the Wellington International ...