Squab pigeons

The squab pigeon. A white Carneau/King Hubbard squab at the age of two weeks. Note the large breast muscles common in utility pigeons.
The practice of domesticating pigeon as livestock may have come from the Middle East; historically, squab or pigeons have been consumed in many civilizations, including Ancient Egypt, Rome and Medieval Europe. Texts about methods of raising pigeons for their meat have been dated back to AD 60 in Spain. The term "squab" formerly included the meat of all dove and pigeon species, such as the Wood Pigeon, the Mourning Dove, and the now-extinct Passenger Pigeon. Such birds were hunted for their meat because it was a cheap and readily available source of protein.

In the Tierra de Campos, a north-western region of Spain, the agricultural practices of keeping cattle, sheep, crop rotation and brush burning changed the land from forests into plains. Grain crops were the major agricultural activity, followed by squab meat. From the Middle Ages a dovecote (French pigeonnier) was a common outbuilding on an estate that aimed to be self-sufficient. The dovecote was considered a "living pantry",[4] a source of meat for unexpected guests, and was important as a supplementary source of income from selling the surplus birds. In medieval England, squab meat was "highly valued", although its availability depended on the seasons - in one dovecote in the 1320s, nearly half the squabs produced were in the summer months, and none were in the winter months. Caelius Aurelianus, a Roman physician, regarded the meat as a cure for headaches, but by the 16th century, squab was believed to cause headaches. In the 14th century humorism book Health Regime, squab was regarded as a "hot and moist" food, whereas the meat of old pigeons were regarded as hot, dry and "barely edible".
More recently, squab is almost entirely from domestic pigeons. The meat of dove and pigeon gamebirds hunted primarily for sport is rarely called squab. Utility pigeons have been artificially selected for weight gain, quick growth, health when kept in large numbers, and health of their infants. Industrially raised pigeons have young which weigh 1.3 pounds (0.59 kg) when of age, as opposed to traditionally raised pigeons, which weigh 0.5 pounds (0.23 kg). Ten pairs of pigeons can produce eight squabs each month without being fed by the pigeon keepers, pigeons which are accustomed to their dovecote may forage and return there to rest and breed. For a greater yield, commercially raised squab may be produced in a two-nest system, where the mother lays two new eggs in a second nest while the squabs are still growing in the first nest, fed by their father. Establishing two breeding lines has been suggested as another strategy for greater yield, where one breeding line is selected for prolificacy and the other is selected for "parental performance".