Management of wild waterfowl has become increasingly intensive. Many birds now hatch in managed nesting cover or in artificial nesting structures, use man-made wetlands, and winter on crowded refuges while consuming a grain diet The water they use is often limited in supply and may contain residues from its many prior users. Unfortunately, intensified management often results in new problems, among which disease is important There are many similarities between the current form of management used for some waterfowl and that used in domestic animals. In both, the objective is to maintain a...