A pregnant female who is about to lay eggs will have a large lumpy belly. If you gently palpate her belly, you can feel the eggs inside her. You may also notice a slight hump in her back to accommodate all the eggs. She will have a big appetite in the weeks before she lays eggs and needs extra calcium in this period and for a few weeks after laying eggs. She may lose her appetite a day or so before laying eggs (although this female ate just hours before laying eggs). When she is ready to lay eggs, she will start digging a lot in her enclosure. This is when it is time to give her a comfortable place to lay her eggs.
This pregnant female laid 28 eggs the very next day: