Pigs have been domesticated for more than 10,000 years and have become very important parts of many cultures as a rich source of protein. They are intelligent animals that are thought by some scientists to be smarter than dogs, and so people have developed a very close relationship with these animals within a farm environment.
Pigs aren't all raised the same way, bu they are rather raised in a number of different ways. The most common way is to rear them on pasture, where they are free to run around and graze.
In some parts of the world, pigs are fed on grain and kept in an enclosed space. This type of rearing is called intensive rearing. In Australia, most pigs are reared on pasture, but the country has a long tradition of intensive rearing as well.
How pigs are reared does affect the ultimate taste of the meat product that's derived from them. There is a strong belief that the happier the pig, the more natural it tastes.