Used to be that tamed boars were afraid of fire, such as torches, so it was fairly easy to build a lane out of fences and chase them with a torch in hand and that would move them along fairly well... Of course they made it so tames are no longer afraid of fire, but I think they should make it so that if friendly fire is turned on they will once again be afraid of the fire until FF is turned off again. Another idea would be to add something in the game such as a "leash" you can put on tames to lead them to new pens or locations, or onto boats.