So do 2 star boar and wolf spawn as 2 star or do they become 2 star? I'm hunting for another 2 star boar now that I won't try to transport. Should I kill all the boars by the stones or do 2 star develop over time from some trigger?

I found a 1 star that was not by a runestone. So far breeding tame around a runestone has not produced any star piggies.