G'day Kevin,
Yep, in the wet season, the entire northern quarter of Australia turns into a lush, green swampland. All the rivers and creeks are full, and sometimes struggle to dump the excess water into the ocean (that's when we get floods). Any minor depression or valley becomes a water course. Because of this, the animals are able to scatter. The pigs are continually travelling during this time, with no boundaries or territory or pattern, and it is unlikely that they'll visit the same place twice. Usually we only see there tracks, although very, very occasionally, we bump into one. More often than not, it is as though the pigs don't exist, except for the damage they leave behind, digging the place up. Donkeys, thankfully, keep to more of a territory, even during the wet, which gives us motivation to venture out.
Cheers,
Ben