When pigs are not spayed or neutered they most often develop behavior problems, and often will develop some behavior problems due to lack of the owner misunderstanding them anyway. They are very smart animals, with an intelligence level of a five-year-old child, meaning they can weigh their options and think things out before following the rules. They are quite capable of training people to get their way. Pigs get extremely attached to their family, whether it be their siblings or the human family they live with, they show their affection differently than dogs and each one has a very different personality much like people do. When separated from their loved ones or family they become extremely depressed, they can cry real tears like people and even sometimes die from a broken heart.