They do this in the wild as well. I agree a better place for them to be, however, these are rescued, to my knowledge, and would be unlikely to survive if released.
Aww.. I hope they have a pool of water to swim in~ and I think they play with stones because they want and need something to do and they instinctively use stones to crack the shells of the things they eat! :)
Otters commonly play with rocks , they sometimes well even carry around their favorite to play with it use as a tool. So no it's not trying to eat them out of hunger
+muurrarium With the exception of the chain (obviously), this is all normal behavior. In the wild they select favorite rocks which they use as a tool and store in a special pouch on their bellies. Otters will spend hours rolling around and playing with their favorite rock!
