ohms/resistance is the mm test I'd do, dependent on gaining access to an rj45 in the camera housing and not finding the wires soldered to the board. You could map out the good end of the cable by putting a test lead on each end of the wire, but if the individual wires are soldered to the board, not sure that would help. stupid squirrels.
... it's already broken, you should totally open the camera housing. I would (and I'd probably buy a new one also).