Board Thread:Questions and Answers/@comment-27598407-20160206111656/@comment-25113070-20160206125440

Even birds have belly buttons, they are just less pronounced than in mammals. The developing foetus still needs a link to the yolk sac within the eggs. So even egg laying monsters will have bell buttons.

KC also stated that Egg laying species will have a short term of pregnancy where the egg will grow larger while inside the mother. After they will then lay the egg and it will develop as a nomal egg. But when an egg laying species does not become pregnant they will still lay an egg or two every so many days/weeks. Just that this egg will be about the size of a chickens egg rather than the far larger fertalised eggs.