JoeF,
I gotta agree with you on the meanness of an old sow hog.
They will hurt you faster than any cow or bull I've ever seen.
I used to help a buddy take care of his hogs and at piggin time some of his old sows were so pissy you had to carry a scoop shovel or pitchfork just to shut them in their houses at night.
We were cutting needle teeth and tails and giving iron shots and I had to stand in the front of the house with a shovel to keep the sows out. That's with the door closed.
His sows were meaner than most.
I had some a few years before that when I was in high school and they were purebred York, you could sit with them while the were giving birth.
Possibly just the way they were handled.