There are more chickens in the world than any other bird. In fact, more than 50 billion chickens are reared annually as a source of food, for both their meat and their eggs. Chickens farmed for meat are called broiler chickens, whilst those farmed for eggs are called egg-laying hens. Laying hens have been bred for egg laying. The 346 million chickens used each year for their eggs, called “laying hens” by the industry, endure a nightmare that lasts for two years. Modern commercial hens produce a very high yield of around 300 eggs a year. Chickens will naturally live for 6 or more years but after 12 months of laying, the hen’s productivity will start to decline. They are taken from breeding farms at 18 to 20 weeks old.