I have also read that your shrimp will molt when put into a new tank as a respose to stress. Not bad stress...but just the changing...
Once they're settled, you'll find a molted skin every once in a while. Don't be alarmed if some of them look JUST like a shrimp. I have (a few times) been convinced that one of our shrimp had died, because I saw the dead body in front of my face, & then he'd come peeking out from behind a rock.