lol dunno where you got 2-20 weeks from
typically speaking, more like 21-40 days till hatching, you will see when and if they hatch, as they will stay connected under her tail until they are ready to let go. Remember that the eggs are sensative on these and a slight shock in location,temperature and water conditions and they may never hatch. you may need to remove them so she can breed again.
The female will continue to breed for the rest of her life much like a rabbit.
the aussie "crays" can live up to a human beings average lifespan.
depending which one you have, some get to over 18" long. some are also coldwater and some are tropical.
I have never heard of or seen their bellies pop open and have not seen them eating there young. admittedly I wasn't paying to much attention.
Is it black, brown or blue?
It will also have ridges running down it's head, how many are there??
Does it have fat and short claws, or long and skinny ones?
you do realised there are hundreds of different types ?