Wild and domestic pigs in a semi-natural habitat spend a large proportion of their active time foraging. The behaviors involved are exploration, grazing, manipulation and rooting. Pigs housed in a low-stimulus environment, commonly present in intensive indoor farming systems, without foraging opportunities, are more likely to exhibit behavioral disorders such as tail-biting. 

The motivation to engage in foraging behavior is high even when nutritional needs are met by a concentrated diet. In fact, it has been shown experimentally that pigs tend to prefer a feed supply that they have to search for themselves to one that is freely available. 

In some housing systems, straw is offered to the pigs as forage. If sufficient amount of straw is available, pigs can root, manipulate and eat it. While many positive effects of straw on pig health and welfare are known, it is still unclear to what extent straw can satisfy the motivation to root. 

FiBL therefore aimed to investigate whether straw can satisfy pigs' motivation to root. For that, fifty-seven fattening pigs were housed in three groups. The three groups differed in the material provided in the lying area: one group had little straw, one group had a lot of straw and one group had a thick layer of compost in the lying area. 

Pigs were given two choices: apple pieces freely available in a trough ('feed') and apple pieces mixed with wood chips ('root'). The pigs had to decide whether to eat the apple pieces as they were or to root for them. Pigs that had compost available in the pen were slightly less likely to choose the rooting condition. These results suggest that compost may be superior in satisfying rooting motivation.

_{More information can be found on the project here:} 

<sub>1. WelFeed – Increasing welfare in feeding and feed intake of pigs, FiBL. [accessed 2024 Dec 9]. https://www.fibl.org/en/themes/projectdatabase/projectitem/project/2176
2. How do different amounts of straw as well as compost in the home pen affect the rooting motivation of growing-finishing pigs?, ScienceDirect. [accessed 2024 Dec 13]. https://www.sciencedirect.com/science/article/pii/S1751731124002623</sub>