21. That has kept Minnesota relatively free of the mammoth factory farms that have polluted Iowa. 22. Dr . Lutz continues her ongoing efforts to end the plight of animals in factory farms . 23. He describes this experience as a direct contrast to the marketing tactics used by factory farms . 24. "We think there's a really big difference between factory farms and family farms, " she said. 25. Currently few policies, regulations and laws exist that promote limitation of antibiotic use on factory farms . 26. Airplane travel, crowded factory farms and urbanization have all been suggested as possible sources of virulence. 27. That is the waste runoff from factory farms , particularly the huge poultry operation in the Chesapeake watershed. 28. Between 2000 and 2003, Mercy For Animals conducted several undercover investigations in egg-producing factory farms and rodeos. 29. Ammonia is a component of animals'urine, so the factory farms are a significant source of the pollution. 30. The practice of dairy production in a factory farm environment has been criticized by animal welfare activists.
