I agree. Foxes. We've had Crocks wind up in a neighbour's garden, Kickers chewed to bits and found at the bottom of the garden, dog toys disappear, the bunjee cord on a kids' trampoline chewed in multiple places and, in one instance, the power cable for a pond pump was chewed right through. My only regret was that it wasn't actually switched on at the time. They are vandals.