Actually, I believe that pastures
should be zone 3, rather than 2. Zone 2 is more about human food forest, whereas zone 3 would be more appropriately, livestock.
I cannot agree with Jeff about using zone 5 for this. Zone 5 is supposed to be left pretty much
untouched, as it is meant to be a study area where you can observe what nature is doing
without your intervention, so that you can observe how your
land was meant to be used by nature. And also, a 'finished' pasture does not need much maintenance, it still needs to be observed and managed if your livestock depend on it. While it shouldn't require frequent or intensive work, it still will need to be tweaked a bit from time to time, and that requires keeping a close eye on it as the seasons progress. If we don't keep a good visual inspection going continuously, it can deteriorate rather quickly. The further away something is, the easier it is to ignore, especially during the busy seasons.