Battery Hens Campaign: Background Information

Development of Battery Systems

In the first half of this century, the usual method of keeping laying hens in most countries was in small flocks under free range conditions. The hens would usually be locked up safely in a barn at night, but left to roam outside during the day. There was then a move towards indoor housing on deep litter in the 1940s, followed by a marked change to battery cage housing.

The first commercial cages for laying hens were developed in the USA in the 1930s. They were designed for single birds, and consisted of rows of cages (batteries of cages) with wooden frames and wire mesh floors. The separation of the birds from their faeces provided by the wire mesh floors improved hygiene dramatically, reducing disease and internal parasites. Most operations were still manual at this stage - egg collection, cleaning, feeding and watering.

The poultry industry expanded rapidly during World War II, when there was a shortage of beef and pork, with hen eggs providing a convenient source of protein. The trend towards battery caging gathered momentum in the 1950s and 1960s. Cages were changed from single to twin bird units, and later multi-bird units became more popular.

There was also a move towards increased mechanisation and controlled environment systems for battery systems. Artificial lighting allowed controlled lighting patterns, and insulation and ventilation made higher stocking rates possible (for example, multi-tier caging) without excess heating and condensation. The result was the system commonly used today - large windowless sheds, with controlled environment, automated 'housekeeping' and high stocking densities. The industry became more specialised, and there was a move towards larger units - the modern poultry unit may have several thousand, or even more then a million, laying hens.

In countries with a developed poultry industry, including Europe and the USA, over 90% of laying hens are now housed in battery cages.

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