Broiler chickens (raised for their meat) are produced by the millions in industrial facilities concentrated in just a handful of states, and much of the waste they produce ends up polluting the nation's waterways. These are just two issues highlighted in a new report 'Big Chicken: Pollution and Industrial Poultry Production in America' from Pew Environment Group.

Karen Steuer, who directs Pew's efforts to reform industrial animal agriculture, commented: "In just over 50 years, the broiler industry has been transformed from more than one million small farms spread across the country to a limited number of massive factory-style operations concentrated in 15 states. This growth has harmed the environment, particularly water, because management programmes for chicken waste have not kept pace with output."

The report compiles and analyses 50 years of federal and state government data to describe a business that has been remade by industrialisation.

Key findings include:

• In less than 60 years, the number of broiler chickens raised yearly has skyrocketed 1,400 per cent, from 580 million in the 1950s to nearly nine billion today.
• Over the same period, the number of producers has plummeted by 98 per cent from 1.6 million to just over 27,000 and concentrated in just 15 states.
• The size of individual operations has grown dramatically. Today, the typical broiler chicken comes from a facility that raises more than 600,000 birds a year.

The 'Big Chicken' report describes the emergence of concentrated animal feeding operations (CAFOs) and the environmental impact of this industrial-scale production. The process creates massive amounts of broiler litter, the mix of manure and bedding taken out of the CAFO. Growers typically dispose of litter by spreading it on open fields or crop-land but when it is over-applied or poorly managed, rain washes it into streams and rivers, causing significant water-quality problems.

A case in point is the Chesapeake Bay, which is infused with excess nutrients generated by broiler litter from the adjacent Delmarva Peninsula. Maryland and Delaware alone produce roughly 523 million chickens a year, along with an estimated 42 million cubic feet of litter – enough to fill the US Capitol dome nearly 50 times annually, or almost once a week.

Robert Martin, an expert on industrial animal agriculture reform at the Pew Environment Group, said: "The environmental consequences of the broiler business's explosive growth are especially profound in the Chesapeake Bay, one of the nation's most important, scenic and threatened bodies of water. Instead of working to limit the effects of all this chicken waste, the industry has fought to avoid responsibility for cleaning up one of our national treasures."

To address the environmental toll of industrialised poultry production, the Pew Environment Group recommends:

• Limits on the density of animal production based on the capacity of crops to absorb nutrients in a given area, especially in areas without alternatives to managing the animal waste.
• Shared financial and legal responsibility between poultry growers and corporate integrators (the large corporations that contract with growers) for managing waste.
• Monitoring and regulation of waste transported off CAFO sites.
• Requirements for all medium and large CAFOs to obtain Clean Water Act permits.

To view the full report from Pew, click here.