I just bought my son two land hermit crabs. They both seem very active and healthy, but last night just before I went to bed one of them went into a log and managed to wall himself in with the substrate. I have read that they may do this when preparing to molt but I am worried that it may be stress from the recent move. Is there any way to determine wich is the case? And if he is molting what should I do to make this easier for him? Should he be separated from the other? I appreciate any help, thanks.