You are obviously very well informed as well as experienced, and wise to have made a study of the regs for your area. Regs do vary considerably by state. My uncle had a not-that-large hog operation shut down at a considerable loss, in an area far away from any town or city. And that in a mid-western state, not on either coast. States in the Delaware drainage came within a whisper of mandating that all bodies of water, rivers, creeks and runlets over a vast area be fenced off at owner expense, which would have put a lot of small operators out of business. Add state to Fed regulations, and I think we can count on complexity of compliance growing over time. TUnfortunately I have experience in an operation similar to the one referenced above. I started a small hog operation, 100 sows. To diversify my farming operation. Sows were to be farrowed outdoors in A-huts. At 6 weeks of age the piglets were brought inside and finished in large hoop buildings in deep straw. The company, which remains nameless did a great job of selling me on the project. Things went well for the first two years. Anytime I had a pot load ready they were shipped the same week, paid within 4 days of shipping. After this "grace period " shipping was no longer a guarantee. At one time a had 400 head of 9 month old hogs, then once they got to the plant in Iowa they were oversize for their rails. Not only was I out 3 extra months of feed, but was also docked for being overweight. This continued for another year and a half. I finally gave up and quit. No argument from the field agent I dealt with. I simply ignored one of his calls and never heard from him again. This leads me to believe I wasn't the only producer that was upset.
In regards to what McFarmer stated. There are different regulations for the size of the operation and confinement methods used. I researched this thoroughly.
Also, electric fences are one of the best ways to fence hogs. Seems like they can knock over any panel, regardless of how strong. You could not push them over the border of a paddock that the hot wire had been removed from.
Right about those hogs - what they can't knock down, they'll root under and if you get them excited enough (as when they smell death) I think you'd have to give them enough juice to pre-fry them, in order to stop them.