WAngel wing
WAnimal Health Act 1981
WAnimal Health and Welfare Act 1984
WAvian influenza
WAvian keratin disorder
WAvian malaria
WBumblefoot (infection)
WCanarypox
WCandidiasis
WCryptococcosis
WCryptococcus neoformans
WEgg binding
WFatty liver hemorrhagic syndrome
WFeather-plucking
WFowl cholera
WGallid alphaherpesvirus 1
WGamasoidosis
WGlobal spread of H5N1
WHistoplasmosis
WInfluenza A virus subtype H5N1
WInfluenza A virus subtype H6N1
WLymphoid leucosis
WPasteurellosis
WPoultry disease
WPsittacine beak and feather disease
WPsittacosis
W1929–1930 psittacosis pandemic
WScaly foot
WSevere acute respiratory syndrome
WSporotrichosis
WWest Nile fever
WWestern equine encephalitis virus