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Applied Animal Behaviour Science 67 2000 127–135 www.elsevier.comrlocaterapplanim
Preference for various nest box designs in farmed ž
ž silver foxes Vulpes Õulpes and blue foxes Alopex
lagopus
L.L. Jeppesen , V. Pedersen, K.E. Heller
Zoological Institute, UniÕersity of Copenhagen, TagensÕej 16, DK-2200 Copenhagen N, Denmark Accepted 10 November 1999
Abstract
Nest box choice experiments were carried out outside the breeding season on adult silver and blue fox vixens with no previous permanent nest box experience. Nest boxes were varied in height
of placement, number of rooms, presence of entrance room or platform and light conditions. Only one parameter was varied in any one experiment. Both fox species clearly preferred an elevated
multi-room nest box; while silver foxes showed preference for boxes supplied with a platform, blue foxes preferred boxes with an entrance room. There was no significant box preference with
respect to light conditions. The possible welfare implications of the preferences are discussed. q
2000 Elsevier Science B.V. All rights reserved.
Keywords: Silver foxes; Blue foxes; Nest box; Preferences; Animal welfare
1. Introduction
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Farmed silver foxes Vulpes Õulpes and blue foxes Alopex lagopus are tradition-
ally raised in wire mesh cages containing an elevated shelf or platform. During spring, mated vixens are given access to a wooden breeding box placed on the cage floor.
The wild ancestor of farmed silver foxes, the red fox, uses dens for giving birth and rearing cubs. Unoccupied dens have also been reported to be occasionally used for
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refuge by single animals throughout the year Tembrock, 1957; Henry, 1986, 1996 .
Corresponding author. Tel.: q45-3532-1304, fax: q45-3532-1299. Ž
. E-mail address: lljeppesenzi.ku.dk L.L. Jeppesen .
0168-1591r00r - see front matter q 2000 Elsevier Science B.V. All rights reserved. Ž
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The arctic fox, which has given rise to the farmed blue fox, also uses dens for breeding. These and other natural or man-made shelters are frequently visited during the rest of
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the year in the wild Eberhardt et al., 1983 . Thus, wild ancestors of both of the commercially held fox species may seek refuges throughout the year for various
purposes as part of their natural life. Based on this knowledge, several attempts have been made during the last decade to clarify how permanent access to shelters affects
farm-bred foxes in traditional cages, and especially to reveal possible effects on the welfare of the animals.
It has been demonstrated that farmed foxes use artificial shelters in the cages, but that the extent of retreat to shelters appears species-specific and depends on other factors,
such as time of day, season, shelter design, and placement of the shelter. In autumn and winter, silver fox vixens provided with year-round nest boxes use the boxes between 5
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and 25 of their time when left undisturbed Jeppesen and Pedersen, 1991 . In the same study, vixens, having access to nest boxes showed lower base levels of cortisol, were
less fearful towards humans and were more activerexplorative in an open-field test than traditionally held controls; these differences all indicate less stress among animals
provided with nest boxes. In choice experiments involving three differently designed
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boxes, Pedersen and Jeppesen 1993 showed that during autumn and winter both silver and blue fox vixens use shelters and prefer a nest box placed at the top of the cage
supplied with an underlying shelf or platform. Silver foxes spend most time on the platform, while blue foxes seek shelter inside the box. When disturbed, silver foxes flee
to remote areas of the cage, while blue foxes retreat to the preferred nest box.
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Mononen et al. 1998b found that silver foxes provided with a nest box on the cage floor and a platform placed high in the cage spend only 2 of their time inside the nest
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box, but a considerable amount of time 17–92 either on the platform or on the roof of the nest box.
Given the choice between a cage with an open view and a cage with a partly obscured view, silver and blue foxes appear to prefer the open view for both activity and
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resting Mononen et al, 1998a . Ž
. Harri et al. 1998 examined production-related parameters and behaviour in growing
blue fox cubs given access to either a top-mounted nest box or a wire mesh platform. They found no substantial differences, except that cubs provided with a nest box
appeared to be more fearful. This effect could be related to reduced human contact Ž
. Pedersen, 1991 . Comparisons of the reproductive performance of blue fox vixens
supplied with a top-mounted nest box or a traditionally placed breeding box on the cage Ž
. floor showed no differences related to the two box types Mononen et al., 1999 .
Thus, it appears that providing farmed foxes with year-round access to a top-mounted nest box or a platform placed high in the cage may improve the animals’ welfare.
However, inter-individual and species differences seem to play a significant role. Moreover, our information on the usefulness of nest boxes and platforms has been based
on experimental situations in which there have been simultaneous differences in both placement and design of available box types for individual animals. In order to obtain
proper information about the importance of the placement and other aspects of the nest boxes provided, experimental conditions have to be designed in which only a single
parameter is varied.
In the present study, we aimed at investigating adult silver and blue fox vixens’ preference for differently placed nest boxes with respect to height. Moreover, we
attempted to evaluate the animals’ preferences for box types with a varying number of rooms, with entrance rooms or platforms and, finally, preferences between dark nest
boxes and light nest boxes with a transparent roof. Individual foxes with no previous permanent box experience were given free choice between two boxes that only differed
by a single parameter.
2. Animals, materials and methods
