I have heard it said that Tamworths, with their longer snout can work soil up better, but I think you're going to find that most any heritage breed will tear that soil up for you real good -especially once they get big
enough to do some serious damage. This past year we had large blacks, berkshires, and large black/Tamworth crosses. I would say that they all rooted very well. They definitely rooted more when they were on the soft, nut covered forest floor than in summer on the harder
hay pasture with, i guess, less sub-terranian foods available. But they still rooted some there, to my landlord's chagrin. Some people claim that they can keep them from doing much rooting by moving very regularly and managing their feeding a certain way. I haven't really played around with trying to prevent them from rooting, or tried hard to encourage it either.
Rotating them will probably give you more even digging results, healthier pigs, and better pork. If you can use electric fencing to split your 1/4 acre into 4 or 6 smaller paddocks, you would be glad you did. it isn't too hard, and if they are trained to that
fence, you have to rely less on your physical fencing. They will also get fewer parasites, and they could dig each section more than once during their lifetime, which would cut back on weed issues in your garden, and give you multiple beneficial quick impact, then longer rest period cycles for better nutrient cycling, and a more natural buildup of soil biology.