In January 2012, a European directive was passed which prohibited the use of conventional battery cages for laying hens and introduced replacement enriched cages. This had a major impact on chicken welfare and was significantly influenced by Bristol research. The new directive increased the size of a cage from 450cm2 per bird to 750 cm2 per bird, with provision for nest, litter and perches.

A critical milestone was the formal decision by the European Commission in 2008 to ban all battery cages. This decision was also influenced by Bristol research and was made despite significant resistance from the poultry industry and national governments across Europe. After the traditional cage was banned the number of hens in enriched cages was reported to be 210 million birds in 2012 (42% of EU production). Bristol research directly contributed to this major impact on production systems and welfare.

However, scientific uncertainty regarding these welfare benefits and optimum design of the enriched/modified cage was highlighted by the poultry industry. In particular, it was suggested that mortality would be higher due to increased space as well as a fall in productivity and egg quality. In combating this perception, the Bristol research on the welfare impact of enriched cages was crucial to inform the subsequent Commission Review. After reviewing the scientific evidence, the European Commission was satisfied that the science did justify the proposed ban on conventional cages. Thus, Bristol research contributed to both the content and implementation of the directive. Following this, other countries around the world have also banned or are in the process of phasing out battery cages.