Tens of millions of farm animals cross state lines every year, traveling in cramped, stressful conditions that can facilitate the spread of disease. Disease Rates, Livestock, Chickens, Avian Influenza, Swine Influenza, Law and Legislation, Animal Abuse, Rights and Welfare, Food Contamination and Poisoning, Bacteria, Factory Farming, Meatpacking Plants and Slaughterhouses, Pigs, Antibiotics, Cattle, your-feed-science, your-feed-health, your-feed-animals Tens of millions of farm animals cross state lines every year, traveling in cramped, stressful conditions that can facilitate the spread of disease. NYT > Business