Behaviour in female mink housed in enriched standard cages during winter

This study evaluated whether adding environmental enrichments to a standard housing system during winter could decrease stereotypic behaviours in female mink. The study was conducted on two private farms (F1 and F2) in southern Sweden. In total, 75 farmed mink on each farm were housed in standard cages, with either a wire net shelf, a plastic ball, a plastic cylinder or all three enrichments together. Standard cages without enrichments were used as a control. All animals in the study were born and raised in a standard cage system without enrichments. The animals were housed in the enriched cages from early December, at approximately 7 months of age, until the beginning of March. Behavioural observations were made in January–March during three observation periods (10 consecutive days each) on each farm. The behaviours were recorded using one-zero sampling during 2 h prior to feeding and 2 h afterwards. There were no significant differences in stereotypic behaviours between treatments at F1, but stereotypic behaviours decreased significantly (P < 0.05) in mink with access to wire net shelves at F2. Stereotypic behaviours were most often performed before feeding and differed in occurrence between periods (P < 0.001). The total number of interactions with the enrichments differed between treatments (P < 0.001), and was highest for the wire net shelf enrichment on both farms. In conclusion, our results indicate that a wire net shelf, plastic cylinder, ball or all these three enrichments together were not sufficient to decrease or interrupt stereotypic behaviours that had already developed in standard housing during winter.