Pigs prosper when living in small, stable groups. They thrive on contact with each other and have a complex language. They use a range of vocalisations to maintain social contact, sound alarm and distress to conspecifics. Aggression amongst wild pigs who have ample space is based on a dominance hierarchy related to age and size. This hierarchy is maintained by pigs using threatening and submissive postures and signals. Expression of many of these behaviours on factory farms is limited and this alone can have a serious impact on welfare.
On factory farms, every aspect of pigs lives is managed by the farmer, including companions, stocking rate, reproduction and feed. Pigs are often housed together in groups of the same age, gender and weight which means newly-introduced pigs fight to establish a hierarchy. Pigs can be aggressive towards each other, particularly if they are unfamiliar individuals and Viva! has documented on many pig farms where the smallest piglets are bullied by larger individuals due to overcrowded conditions.
Yet whereas unfamiliar pigs crowded in industrial units will become aggressive and antagonistic, in the wild, pigs are gregarious, sociable animals and the members of a sounder keep close contact at all times, often engaging in social behaviour as huddling and grooming. They sleep in communal nests that adults help to maintain by adding fresh bedding materials such as branches and grass.
Given the chance, pigs make caring, loving mothers and their babies do not naturally wean until around three or four months old. Early weaning causes stress for both mother and young, and the risk of disease for piglets.
A mother pig is very protective of her babies. In the wild she is isolated from the sounder for one to two weeks, and this period of close contact with her piglets encourages the formation of strong bonds. One or two days after giving birth, the sow begins to leave on short foraging trips, though staying close to the nest and her young.
Exploratory behaviour, such as rooting, develops within the first few days of life, and the piglets soon begin on short adventures with their mother. It is heart rending that most mother pigs are trapped in crates to give birth, unable to build nests, deprived of being able to teach their young ones to forage and explore a beautiful and complex world. They are denied all that is natural and wondrous.
David Wood-Gush and Alex Stolba, University of Edinburgh, after several years of studying domestic pigs in a semi-natural enclosure stated:
"The social behaviour of the domestic pig seems to resemble, in all important respects, that of the European wild boar, Sus scrofa, when the domestic form is allowed to live in semi-natural conditions" (41).
Despite being domesticated, pigs retain their essentially wild boar traits, reverting to the wild given half a chance. Pigs are highly intelligent animals who would roam several kilometres each night, rooting and exploring their surroundings. They are fun-loving, social, complex, tactile and full of joie de vivre. To house them in dirty, wooden-slated pens with only a ball or chain for stimulation, if that, is unacceptable, insulting, immoral and cruel. Pigs in Britain (and elsewhere) endure short and brutal lives on farms where their welfare is of far lower importance than production.
Pigs should be left to be… pigs. In mighty oak forests and shrub lands where they belong.