Snakes that eat eggs have an adapted vertebrae that cracks the egg on the way down (at least one species) and those that don't, the shell ends up cracking eventually prior to digestion. They then regurgitate the shell and the white and yoke are digested. A snake would not encounter a boiled egg, but if you made this happen and they sensed it was food (they may not after it has been boiled), then they'd have a problem digesting it because cracking attempts wouldn't help rid them of the shell. It would cause an obstruction to future meals and they would likely rot from the inside out. Please don't try it.