Pigs definitely have a social intelligence that at least rivals those of dogs, if it doesn’t surpass it. Just because we keep them in a way that traumatises them from an early age on, doesn’t mean pigs aren’t socially intelligent. Wild boar and the like form highly complex social structures and are quite able to communicate in between one another. The only thing pigs actually express more than dogs is the utter disregard for anything but their own survival when under duress. This however might be explained by the way they reproduce. Pigs are K-Strategists, whereas dogs aren’t.