What do the dragonriders give dragons to help them breath fire in Smallest Dragonboy?

The dragonriders in *The Smallest Dragonboy* don't give their dragons anything to help them breathe fire.

Dragons in this story are naturally born with the ability to breathe fire. It's simply a part of their being, like their scales or wings. The book doesn't mention any special diet, potions, or external factors that contribute to their fiery breath.