Among the reasons for this are the large litter size that can be reared in captivity, the short time to maturity and the relative ease with which colour varieties may be produced and maintained under captive conditions. During the 1950s world pelt production reached three million and by the end of the decade 11 million kits were produced each year. 25 million mink are now bred each year to meet the world demand for their pelts. Domestic mink were first imported to Europe in the late 1920s and to the UK in 1929. These early farms were generally small operations and as mink were not that profitable many disappeared.
Wild mink are territorial.
However, the cages normally encountered on mink farms rarely exceed 30cm wide x 45cm high x 90cm long and these may be used to house more than one animal, so it is more than likely that animals are highly stressed. This is reflected by such abnormal behaviour as pacing and circling. It is, indeed, remarkable that a wild animal will breed under such conditions, especially as they do not become domesticated and continue to remain wild animals. This is why they pose such a threat if they escape. In spite of being commercially bred for approaching a hundred years, they have not been selectively bred in the way that domestic animals were selected for features such as tameness, meat production, and other adaptations.