Researchers at UC Davis are studying personality traits in pigs to determine the role personality plays in the welfare and sustainable production of farm animals. Kristina Horback, an assistant professor in the Department of Animal Science, is conducting a series of tests with four-week-old female piglets. 
The tests are meant to identify aggressive and social behaviors, along with measuring responses to a variety of stimuli. Aggressive piglets loudly squeal when held firmly, while passive pigs do not squeal as much. The piglets that are first to sniff the others in the pen are generally more sociable.
Due to legislative and marketplace demands, farmers are transitioning back to group pens instead of individual stalls. Pigs are hierarchical, which can cause problems during feeding time. Timid pigs will not compete for food as well as dominate pigs.
Dominate pigs often eat more, which farmers value, however it comes at the expense of other passive pigs. Horback hopes to determine the best set of personality traits that will work best in a group environment, but there is still more research needed.
The personality research is assisting farmers and pigs adapt to the group housing while protecting social and passive pigs from the more aggressive pigs.
Watch the UC Davis video below.