Ball pythons are picky. If they havent tried it, then they don't see it as food. Once they try it, they know that it's okay to eat. They will starve themselves to death!!! With live they won't because they know it's food. Believe me, there are snakes that will never switch. They usually don't take f/t as babies. It's usually closer to 200 g when the majority switch. I know it's frustrating, but you have to comply with their behaviors.