An increase in demand for poultry and eggs during World War II triggered the development of modern production practises. To meet the nutritional needs of more people on the same amount of land, with fewer workers, new breeding, feeding and management methods were required. Soon we saw hens move from straw floors and farm yards to cages in highly automated barns. Hens are now housed in clean, ventilated buildings where temperature, humidity and lighting are controlled for year-round comfort. Fresh food and water are constantly available.
Control systems regulate heat, light and humidity for day and nighttime patterns.
Eggs automatically roll from cages onto conveyer belts for prompt collection. Even manure management is much easier. Cage designs allow waste to drop right out of the cages into a manure disposal pit, keeping both the egg and hen clean and safe from disease. It is a matter of genes. Some breeds of hen such as the Rhode Island Red lay brown eggs, while others, like the White Leghorn lay white eggs.