Nearly 46 billion such chickens are reared in the world every year, five billion of them in the European Union -- higher than in any other livestock sector in the 25-nation bloc.

The draft law, authored by the European Commission, will be presented to EU agriculture ministers next month and needs their agreement before it can become law.

It sets out hygiene standards for the ammonia-ridden litter that piles up on the floors, rules for ventilation inside the mostly windowless sheds and tackles the key area of stocking density: or how many birds may be packed into a specific area.

Stocking densities vary widely across the EU. The European average is 40 kg of bird weight per square metre, and slightly higher in some countries like France and the Netherlands.

The bill recommends 30 kg as a base standard but with leeway for intensive-rearing operations to raise this to 38 kg if they meet welfare standards in areas such as litter and ventilation.

"Animal welfare is not just about ethics, it is also a quality issue for consumers," EU Health and Consumer Protection Commissioner Markos Kyprianou said in a statement.

"Intensive farming methods in this sector have led to significant welfare problems and consumers have repeatedly expressed concern about the welfare of chickens," he said.

At present, Europe has no specific laws to control the broiler trade. A few countries, like Sweden and Denmark, do have strict laws in place but most have none.

Animal welfare groups broadly welcomed the proposed law but were dismayed that it does not address one of the most controversial areas of the broiler trade: congenital defects, leg problems such as lameness and circulatory problems that they say occur as a result of cramped and poor conditions.

"The proposals...are simply not fierce enough to reverse the trends of ever-worsening broiler welfare," said Sonja Van Tichelen, director of lobby group Eurogroup for Animal Welfare.

"Across the 25 member states, some three thousand birds die every five minutes under the combined strain of genetics and production," she said in a statement.