Manure is not used by the large, commercial livestock-feed manufacturers because they would be required to perform expensive tests to detect pathogens and toxins. Distasteful as it may seem, chicken and turkey droppings can be fed safely if handled properly. This involves correctly stacking the manure for four to eight weeks while the naturally generated heat raises temperatures to 160 to 170 degrees Fahrenheit, high enough to destroy bacteria and toxins. Some farmers say they feed chicken manure raw to cattle straight from the broiler house, which virtually ensures problems. Studies of manure-feed safety, argue the authors of the Preventive Medicine report, have been conducted largely in controlled environments, not in the casual, unregulated conditions on most farms.
Few studies address public health aspects, and there is an overall dearth of published information.
If you don't, it's like playing with matches around gasoline. The contents of animal feed are attracting more attention as a result of the outbreak of so-called mad cow disease in Great Britain and concern that similar problems could occur here. The cattle are thought to have contracted the disease by eating rendered brains and spinal cords of sheep infected with a condition called scrapie. While scrapie is far less common in the United States, on August 4 the FDA ordered a halt to feeding all slaughterhouse wastes to U.S. cattle and sheep as a BSE safety precaution. Seventy-five percent of the nation's 90 million cattle had been eating feed containing slaughterhouse byproducts, so the ban raises the possibility that more farmers and feed manufacturers will turn to cheap additives like manure and other questionable waste products.