I don't even think we have to do that. They are already filling their own cities with hepatitis and Bubonic plague. Pigs might be a good idea though but we'll bbq them outside because if it gets to that, they're going to pretty darn hungry in those locked up cities. Portland doesn't have a lot of entrances and exists that are easily navigated. Just stand across the river and blow the BBQ their direction. It would totally demoralize them if it comes to that which I hope it won't. Portland was designed to be besieged. There's not even any good spots within ten miles of the city limits for them.