I realize this is an old post, I just joined a few minutes ago and stumbled on this thread. I was told that you could take a tub or small swimming pool, like the plastic blue ones for small children, and place it to where it’s not level, sloped, and fill with sand. Add water till it’s full on the downhill side and completely dry with only wet or moist sand on the uphill side. Add crawdads and some rocks for crawdads to hide and add raw chicken liver. The idea is to allow the crawdads to feed therefore they will then grow, burrow in the sand and molt. You can keep repeating the process and always have a supply of soft shells. Keep in mind, a guy once told me this would work but I’ve yet to try it myself.