The periparturient behaviour of silver-fox females inside traditional and modified breeding boxes was video-recorded. The behaviour was analysed from 24 hours before parturition to 72 hours after, and in three diurnal periods. Twenty litters had the traditional simple breeding box,
whereas 14 litters had a box with a narrow entrance tunnel. Compared to females in traditional boxes, females in tunnel boxes spent more time sleeping inside the box both before and after parturition, cleaning newborn cubs and grooming cubs while lying down, but less time looking out of the
box. Excavation performed on the floor prior to parturition was performed equally often in both box types. The differences between box types were particularly pronounced for primiparous vixens. During the three postparturient days most differences in behaviour between box types were only found
during working hours (0800-1500h). At this time females in non-tunnel boxes spent considerably less time sleeping and more time in locomotion within the box, looking out of the box, walking into or out of the box, standing partly out of the box, or staying out of the box, than females in tunnel
boxes. Cub mortality was lower in tunnel boxes than in non-tunnel boxes. The results indicate that females in tunnel boxes had a more relaxed behaviour and were able to nurture their offspring more effectively. They did not watch their surroundings as frequently as females in traditional breeding
boxes. Giving silver foxes a breeding box with an entrance tunnel may improve the welfare of both female and offspring.