What makes a Kentucky Derby champion? Big hearts, immense lungs and powerful legs Horse racing’s most-watched event will draw attention not only to the animals’ skills, but also to concerns ...

What makes a Kentucky Derby champion? Big hearts, immense lungs and powerful legs On display at Saturday's Kentucky Derby will be the speed and agility of these 1,000-pound animals.

What makes a Kentucky Derby champion? Big hearts, immense lungs and powerful legs On display at Saturday's Kentucky Derby will be the speed and agility of these 1,000-pound animals.

On display at Saturday's Kentucky Derby will be the speed and agility of these 1,000-pound animals.

What makes a Kentucky Derby champion? Big hearts, immense lungs and powerful legs On display at Saturday's Kentucky Derby will be the speed and agility of these 1,000-pound animals.