<unk>  mice have a spontaneous deletion in the FOXN1 gene. (Humans with mutations in FOXN1 also are athymic and immune deficient.) Mice with a targeted deletion in the FOXN1 ("knockout" mice) also show the "nude" phenotype. Since<unk>  females have underdeveloped mammary glands and are unable to effectively nurse their young,<unk>  males are bred with heterozygous females.
Nude mouse
Biobreeding rat
Charley horse
Cold turkey
Silver Spring monkeys
Wellbee
Pest house
Litter 