Eastling
Really sorry to hear about this - a horrible thing to happen.
Energisers are governed by many standards - they send out thousand of volts, but milliamps, and it is amps that do damage.
Both mains and battery energisers would never deliver a fatal blow to a pig. Toads, rabbits and the occasional hedgehog can have issues with electric netting as they get entangled at night, but strands at 6 inches should cause no harm to any animal, and a Defra trial supports this.
As you have suggested, it is most likely that she suffered some damage as she was being shocked, and back damage from thrashing looks like the verdict.
I have never heard of an incident like this before, and horrible as it is, should never hear of it again.
Again Eastling - really sorry to hear about this.