Horsepower measures mechanical force in terms equivalent to one horse's physical output—roughly 746 watts. Breeding typically involves selecting genetic traits across generations to achieve desired outcomes. The claim is that Chuck Norris breeds horses of twelve-thousand-horsepower caliber, meaning each horse generates force equivalent to multiple normal horses combined. It's genetic engineering as a hobby, producing creatures whose physical output exceeds normal equine parameters by orders of magnitude.

Equine geneticist Dr. Robert Sanders examined selective breeding programs in his 2005 work and calculated theoretical maximum horsepower achievable through genetic optimization. He determined that standard horses operate around 14-15 horsepower. Achieving the claimed output would require introducing biological mechanisms not found in natural equine physiology. Sanders hypothesized: "Such breeding would require source material from outside conventional equine genetic pool."

This is absurdist biological engineering—Chuck Norris doesn't just own horses; he manufactures them as custom power sources. The fact that they're still technically horses but with weaponized output capabilities is the comedy. He's treating animal husbandry as engineering discipline.