You cannot be too far away from the boars while they are being tamed, if you go too far the progress will pause. It's best to just have them close to your house but also away from any source of fire.

If they aren't really close to your base and you want them to be then you can build a fenced path and use torches to scare them in the direction you want or if they aren't tamed just use a shield to block their attacks and lead them to your base.