 Because poultry litter can contain recycled cattle proteins as either spilled feed or feed that has passed through the avian gut, the FDA was concerned that feeding litter would be a pathway for spreading mad cow disease.In 2004, FDA decided to take a more comprehensive approach to BSE that would remove the most infectious proteins from all animal feeds.The FDA decided at this point that a litter ban was unnecessary in part based on comments by the North American Rendering Industry.