How long do mystery snail eggs take to hatch?
If you don’t see little snails after breaking a 4 weeks old clutch, it can be that the eggs aren’t fertilised or that the air moisture was too low. In the latter case the yolk is very thick or the eggs are completely dried out and filled with air. You might want to wait until the snails appear on the natural way (it can take several days before they all are hatched), but keep in mind that if the clutch isn’t kept moist enough, the young snails won’t be able to make their way out and subsequently die.