How many chickens can you fit in a cage?
Devised in the 1940s, battery cages were a response to an increase in hen productivity as a result of major breakthroughs in nutrition and breeding (Duncan, 2001). The movement was toward greater automation with a goal of reducing disease transmission while increasing hygiene in the poultry industry. As a result, there was a huge reduction in the number of producers and an increase in the capital investment needed for egg production and processing (BC Egg Producers, 2001). This led to a system that produced the maximum number of eggs for the lowest possible price, as well as seriously compromising the welfare of hens.
In a battery cage, the rate of food and water, and duration and intensity of light are tightly controlled. There is no access to the natural environment, nor any opportunity to conduct natural behaviours such as perching, dust bathing, wing flapping or nesting. These cages inhibit almost all the natural behaviours of hens (Rollin, 1995).
Battery barns in Canada hold thousands of cages, each holding five to seven birds, in tiers of two to eight cages high, with farms averaging 18,368 birds (Agriculture and Agri-Food Canada, 2006). However, farms can range from anywhere between a few hundred to more than 400,000 hens. The average laying hen produces about 300 eggs per year (25 dozen).