Hi Langdon,
Just partly answered this in your other post

No hard and fast answer - depends on size, soil, usage, weather and probably other factors if I thought about it.
The answer lies in "why rest it?"
possible reasons to rest ground would be
1. worm burden - unlikely with small numbers of pigs who are treated
2. ground severely poached (we rest areas that are poached, and cast grass seed onto them, I then take a quad bike with small roller over it to flatten and bury the grass seed - leave it a coupe of months and it recovers quite well - not exactly pasture but good enough for pigs
3. Letting an area visually recover
We swap pigs between areas to achieve 2 & 3 - particularly the sows who can turn over an area very rapidly.