I have all my animals in rack systems. I opt to not use any substrate when I think they are about to drop. If you are diligent about taking notes, you should have a pretty good idea when the girls will lay their eggs. Watching their body language helps too. I just pull out the newspaper they are usually on, so the eggs don't stick, and remove the water dish, just incase that turns into a great place to lay eggs. Don't want any mishaps. I do these things no more than 3 days prior to when I estimate her to lay.