What are the horses racing at the Kentucky Derby?

It is limited to three year old thoroughbreds only. No Belgians or mustangs need apply. Geriatric Gypsy Horses go away, Premature ponies will be escorted out. All size challenged animals like Hanoverian's may leave their applications in the circular file cabinet next to the watercooler.

They are bred to run. Someone said that the Thoroughbred has been bred and inbred with a locomotive for a heart and champange glass stems for legs. Perhaps some form of Genetic discipline or engineering will be required.