Hi there....how old are they, and what are they in ? Do you keep a lid with holes on it ? If you're sure they're fertile, they need more water added to the laying medium. Very gently add some water around the eggs....if you get any water dripped on the eggs, have a paper towel handy to dab it off right away. Water directly on the eggs can kill them. But they should plump up if you add a little water around them.