Genotype   Phenotype
female male
H H   Hen feathered     Hen feathered
H h   Hen feathered     Hen feathered
h h   Hen feathered     Cock feathered
Sex-limited Feathers

Plumage in domestic fowl is controlled by an autosomal locus whose expression is modified by the individual's sex hormones: cock feathering is longer and pointed than hen feathering.

Leghorn hh hens can be induced to produce cock feathering by removing the ovaries, indicating that female sex hormones inhibit cock feathering.