What is "battery cage"

n. A small cage in which a hen (chicken) is kept to lay eggs.

Battery cages are a housing system used for various animal production methods, but primarily for egg-laying hens. The name arises from the arrangement of rows and columns of identical cages connected together, sharing common divider walls, as in the cells of a battery. Although the term is usually applied to poultry farming, similar cage systems are used for other animals. Battery cages have generated controversy between advocates for animal rights, and industrial producers.

It was estimated that over 60% of the world’s eggs were produced in industrial systems, mostly using battery cages. In the US, over 90% of the 300 million egg-laying chickens are housed in battery cages. In the UK, statistics from the Department for the Environment, Food and Rural Affairs (Defra) indicate that 50% of eggs produced in the UK throughout 2010 were from cages (45% from free-range, 5% from barns). However, introduction of the European Union Council Directive 1999/74/EC which banned conventional battery cages in the EU from January 2012 for welfare reasons, means the number of eggs from battery cages in the EU states is rapidly decreasing. The EU ban was proposed when international scientists independently observed signs of extreme abnormal behaviour (including cannibalism) in caged hens.