Are butterball turkeys raised on butter?

The name "Butterball" is a brand name, and it doesn't have anything to do with the turkeys' diet. Butterball turkeys are raised like most other commercial turkeys - on a diet of grains and other feed.

The name "Butterball" likely came about because the company's turkeys were bred to be larger and meatier, leading to a more "butterball"-like appearance.