Infinity, or zero.
Stand (or "stand") very far away from a planet. Toss the pig perpendicular to the line to the planet. The pig is now in a long, long orbit. It will travel a nigh-infinite distance, though always returning to the starting point.
No matter the half-orc monk's level, the typical half-orc monk that possesses Strength 18 that's using only material from the core rules can't throw a pig.
Step 1: Find the pig
Officially, pigs have no statistics. The Player's Handbook lists on Table 7–3: Trade Goods lists one pig as an item with a cost of 3 gp (112), but, otherwise, the entire Wizards of ...
TL; DR - 85 feet or 170 feet.
Half Orc is size Large
Pig is not resisting
Pig is size medium (No more than 300 lbs)
Distance is adjusted for strength
Racial ability or Improved Rock Hurling Feat
Strength requirement for the feat is ignored
From the 3.5 sourcebook Races of Stone, there are two applicable feats, Fling Ally and Fling Enemy. The ...