[1.2.198]Goldrich Event, Sleepywood Expansion?

If there were 12 gold pigs it would be mentioned. There are 12 copies of the eggs though, so more than likely the drop is related to some quest that you have active and that's how it varies for level ranges.

Kind of makes sense, but the pigs for lvl 50~60 have around 500 hp, while the ones for 70~80 have 1300.