Pigs can be quite vicious and dangerous. A lot depends on the species of pig. There are several thousand species of pigs and they vary considerably in size, shape, habits etc. You have the tiny "Nesting pigs" of Fiji that are not much bigger than a cat. Build a nest similar to a bird, chew a cud like a cow and are very docile, (also furry) then you have the "Russian Boars" Which are very lean, large in size, highly aggressive and are vicious carnivores.
the ones commanly raised by farmers will range somewhere between those. City folks seldom see a full grown pig. Pigs grow for about 3 years, if left to grow. Typicaly people that raise them for meat butcher them when they are about 3 months old and weigh 200 pounds. Most full grown pigs will out weigh a cow and are nearly 3 feet high at the shoulders.
the pigs that are typicaly raised by people can be very dangerous.