When the game tests for a chance to spawn the masked pig, it doesn't count oincs in your backpack-type equipment's inventory slots. This may actually be intentional, though it seems a little unintuitive and can cause players who know possessing oincs is what causes him to spawn confusion when they stand around with a couple hundred oincs in their pack and he never shows up.
Steps to Reproduce
Put 100 oincs in a backpack inventory slot and turn the console log on
Put 100 oincs in a backpack inventory slot and turn the console log on
A developer has marked this issue as fixed. This means that the issue has been addressed in the current development build and will likely be in the next update.