First off, pigs are not aggressive by nature but can act aggressively. When they do it is for a reason. You just have to find the reason.
1. they will act aggressive with each other when setting their hierarchy. But soon as the order is set, they go back to being peace lovers.
2. Pigs won't start a fight they don't think they can win. One big reason they seldom start a fight and most of the time will run from a fight.
3. Pigs are emotional animals. We see this everyday in their behavior. They will act aggressively to show anger. Anger at change that is taking place in their lives or around them.
When I play with my cat, who knows if I am not a pastime to her more than she is to me?
~Michel de Montaigne
Did you know there is a permanent way to identify your pet in the event that he is lost or stolen? Microchip implantation is becoming a widely used form of identification. A very small microchip is implanted under your pet's skin with an identification number that is held in a large database. Lost pets can be scanned by animal control officers and shelters to identify your pet and help bring him home. Never fear the loss of your pet again.