It is estimated that worldwide, approximately 80 percent of eggs are produced in battery cages (Canadian Coalition for Farm Animals, 2005). This is in spite of significant effort by the European Union (EU) to push towards other housing systems (Savory, 2004). A significant percentage of eggs from caged hens worldwide arises from North America and Asia egg farming operators, who continue to use battery cages (Duncan, 2001).

Laying hens in the United States are primarily housed in battery cages (Pohle and Cheng, 2009). This is also the case in Canada today (Agriculture and Agri-food Canada, 2003).