Just so happens that Muscovy ducks are the ones on our list. I had heard they were good for grey water ponds (we will be recycling the grey water from our home) as they won't swim in poor quality water. This could also be bologna but I haven't pursued research on them as of yet. I appreciate the heads up on their... err... habits. Will take that into consideration and start out with just a few to see how they fit into our plans.