Canaries have been kept as pets for over 500 years and are bred in many varieties, but some breeding selections have created welfare problems similar to those in extreme dog and cat breeds.
Canaries bred for extreme traits suffer welfare impacts analogous to brachycephalic dogs. The Gibber Italicus breed has been selected for a posture that causes permanent stress on the spine and muscles. Crested breeds with very large crests can experience impaired vision and balance. Selective breeding for very specific song types including the Roller canary involves training methods that suppress some natural vocalizations. Canaries require sufficient space for flight, which most commercial cages do not provide. Aviaries of at least 1 meter length allowing full flight are recommended. Canaries are highly social and benefit from same-sex companionship. Nutritional deficiencies are common in seed-only diets.