Pet them often stay with them for a while every day eventually they will be tame
I have 12 boars and 4 kids
feed them raspberry and red top mushroom.
I built near water since pigs like water in real life, these go into the pond and the other pond around the corner and swim in it.
https://steamcommunity.com/sharedfiles/filedetails/?id=2611270102
https://steamcommunity.com/sharedfiles/filedetails/?id=2611269583