|H H||Hen feathered||Hen feathered|
|H h||Hen feathered||Hen feathered|
|h h||Hen feathered||Cock feathered|
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.