Do yabbys hibernate

Answer 1

Yabbies sleep in the same way that other mammals do. They go into a state of sleep that provides relaxation and rest for the yabbie.

Answer 2

Yabbies tend to hibernate during the colder months by digging into the sand/Gravel. This may possibly be prevented by putting a heater in your tank and setting it at 20 to 30 degrees celcius.