A comparison of the use of resting platforms and nest boxes in growing farmed silver foxes (Vulpes vulpes)

Abstract The use of the interior and roof of a nest box and the use of various types of resting platform were studied in 50 juvenile silver foxes ( Vulpes vulpes ) of both sexes housed singly in traditional fox cages measuring 115×105×70 cm (L×W×H). The experiment was carried out from early July to the end of December. The use of the nest boxes and platforms by the silver foxes was video-recorded for one 24-h period in August, October and December. Furthermore, the use of these furnishings was observed 14 times per week for the whole experiment by a person walking past the experimental cages in the daytime. The video recordings showed that silver foxes spent an average of 2.0±2.7% (median 1.3%) of their daily time in the nest boxes. The foxes were observed in the nest boxes in 0.9±2.7% (median 0.3%) of the direct daytime observations. The average use of the platforms and the roof of the nest box (i.e., one type of platform) varied from 24 to 84% of daily time and from 17 to 92% of the daytime observations depending on the month and the platform or cage type. The roof of the nest box was used more than platforms of corresponding shape and size, and the use of the roof decreased less in the course of autumn than the use of the platforms. This was possibly due to the nest box obstructing the view from the cage floor and restricting the free floor area of the cage. In the early winter, the silver foxes preferred the flat and wide platform to a narrower platform with a slightly u-shaped bottom. This may be due to the wider platforms enabling the foxes to assume more easily the curled resting posture typical in cold weather.