In this case a chained dog would have been perfect... I had all sorts of farm thieves before, they would even come in and dig up Tapioca, or even better the neighbors we knew thought it would be ok to harvest greens early morning in plain sight.. not even trying to be subtle. Dogs are part jackal, they do not allow any strangers. I put a few of the most aggressive ones in warehouse daytime so they don't accidentally bite mailman or 'ok' strangers, then they all roam free at night sundown to sunup. Since they all female, they don't stray far from home.
If need them daytime, just chain them up where needed, to stop the pig from using an accessway, or around a fruiting tree near property border like this.