Effects of group housing systems on behaviour and production performance in farmed juvenile mink (Mustela vison)

Abstract

Juvenile mink were kept in two different group housing systems and their behaviour and physiology compared to that of juvenile mink kept traditionally in pairs. One group housing system was made by adjoining three traditional cages (row system) and the other by stacking a slightly smaller cage on top of a traditional cage (stacked system). Frequent scan sampling observations on behaviour and choice of stay were performed during 3 months on a focal female mink in each system. The occurrence and severity of damages to the fur was registered as well as morbidity and mortality in each system. The data showed that the frequency of stereotypies, auto-grooming and play did not differ significantly between systems. But the stacked system deviated significantly from both the traditional and row system in a number of occasions. There was a higher frequency of surveillance (P<0.01), exploration (P<0.01) and agonistic behaviour (P<0.05) and a lower frequency of sleeping (P<0.05) and eating/drinking (P<0.05) in the stacked system. Morbidity and mortality was significantly higher in both group housing systems (9–11%), compared to the traditional system (0%). Group housing of juvenile mink, as practised in this experiment, could not be recommended from a welfare point of view. If group housing of mink, despite these findings, gets widely adopted, it is crucial that further research continues in order to find the appropriate stocking density, no. of feeding places and nest boxes, and optimal group composition acquired to obtain a good and acceptable welfare level in all individuals in the group.