Which of these is a real medical condition?

Bird fancier's lung is a type of hypersensitivity pneumonitis caused by bird droppings. The lungs become inflamed with granuloma formation.

Bird fancier's lung (BFL), also called bird-breeder's lung and pigeon-breeder's lung, is a subset of hypersensitivity pneumonitis (HP). This disease is caused by the exposure to avian proteins present in the dry dust of the droppings and sometimes in the feathers of a variety of birds. Birds such as pigeons, parakeets, cockatiels, shell parakeets (budgerigars), parrots, turtle doves, turkeys and chickens have been implicated.

People who work with birds or own many birds are at risk. Bird hobbyists and pet store workers may also be at risk.

This disease is an inflammation of the alveoli in the lungs. Initial symptoms are breathlessness especially after sudden exertion or when exposed to temperature change and can be very similar to asthma, hyperventilation syndrome or pulmonary embolism. One of the defining characteristics of bird fanciers lung is that many medical tests will show a normal range of results and it will be identified by X-ray or CT scans showing physical changes to the lung structure (a ground glass appearance).