"But legislation pre-empting state laws on egg production systems would set a dangerous precedent for allowing the federal government to dictate how livestock and poultry producers raise and care for their animals. It would inject the federal government into the marketplace with no measureable benefit to public or animal health and welfare.

"NPPC is gravely concerned that such a one-size-fits-all approach will take away producers’ freedom to operate in a way that’s best for their animals, make it difficult to respond to consumer demands, raise retail meat prices and take away consumer choice, devastate niche producers and, at a time of constrained budgets for agriculture, redirect valuable resources from enhancing food safety and maintaining the competitiveness of US agriculture to regulating on-farm production practices for reasons other than public health and welfare," the organisation said.

NPPC also is concerned about the uncertainty such legislation would generate among US pork producers, who use a variety of production and housing systems. NPPC supports the right of all producers to choose systems that ensure the well-being of their animals and that are appropriate for their operations.

According to NPPC, The US pork industry has adopted programmes – Pork Quality Assurance Plus and Transport Quality Assurance – that educate and certify producers in best practices, and it has adopted "We Care" ethical principles that include producers’ commitments to:

• Raise animals humanely and compassionately.
• Produce safe, nutritious pork.
• Use animal health products responsibly and in consultation with a veterinarian.
• Protect the environment and public health through best practices.

"US pork producers have practiced these principles for decades because it’s the right thing to do," said NPPC.