My experience says stock mesh and electric. With just stock mesh, they will inevitably dig under it or break/uproot/push over one of the supporting posts and sneak underneath. With just electirc, eventually either they throw mud over the bottom strand to short it out or just charge thorugh it. With both, they can't get lose enough, for long enough to break the mesh fence and can't just push through the electric.
Best solution is well strained stock mesh and a couple of strands of electric about six inches inside it.