the number of eggs obtained from poultry during a specific period of time (a month, year, and so on).
Egg production depends on the poultry’s species and breed, hereditary properties, individual characteristics, age, and conditions of maintenance. Chickens yield 220 to 250 eggs per year, ducks 120 to 180, turkeys 100 to 150, and geese 50 to 80. Breed differences in egg productivity are especially marked in chickens and ducks. Hens of egg-laying breeds produce 10 to 12 percent more eggs than those bred for both eggs and meat and almost twice as many as those bred for meat alone. Egg yield decreases with the age of the bird: in chickens, for example, it decreases by 10 percent each year by comparison with the first year of egg laying. A bird is capable of producing eggs for about ten years. On breeding farms it is economically profitable to use the best layers for two or three years; on commercial farms the laying flocks of chickens, ducks, and turkeys are replaced annually.
Egg productivity is a hereditary characteristic that is transmitted to offspring, especially through the paternal line. In the northern hemisphere a bird usually begins to lay eggs in the spring and stops in summer; in the southern hemisphere the highest egg yield is from September to November (spring). With controlled management and the use of scientific methods of feeding, the seasonality of egg laying is leveled out and egg productivity is increased. Chickens begin to lay eggs at three to six months of age, turkeys at 6½ to eight months, and ducks and geese at eight to ten months. To obtain the same number of eggs year-round, a flock is made up of young layers hatched at different brooding seasons.