It is argued that mice have poor colour vision and are insensitive to the colour red, which they in theory perceive as dark. Therefore, the red tinted Bio-Serv Mouse Igloo® is used to provide mice with a dark shelter while enabling humans to monitor the animals through the shelter without disturbing them. However, we do not know if mice like the colour red. Therefore, this study investigated whether mice prefer an amber or blue igloo over a red igloo, still making it possible for humans to see through the igloos. A preference test consisting of 3 cages each containing a different coloured igloo, connected to a barren central cage, was conducted for 11 h 20 min in 32 female B6 mice. The results showed that some female B6 mice did not like to use the Bio-Serv Mouse Igloo® as a shelter, regardless of colour. Almost half of the mice chose to stay outside the igloos, but when choosing an igloo the mice preferred the blue or amber igloo over the red igloo.