HI ALL. I have several ducklings I hatched out, who are now pretty much adults; maybe 90% grown. I noticed that they have green spots on their beaks..looks kind of like algae? Water wise, they haven't had an actual pool yet, but have had a mini pool about 4 inches deep, 2 feet sqare. They also have a regular waterer. The water in all is changed every day. Most of them don't seem much interested in the mini pool. They were let out of their cage to range around inside big run with plenty of grass and bugs about a month ago. I have 7 other true adult ducks totally separate,, way away, and those do have a baby pool which they love, they free range during day and put up at night in a tractor..None of my adult ducks have any sign of green stuff on them.. I've searched a lot thru this site and can't find any answers as to what is going on with the green...ALL of my ducks are healthy, active, and absolutely no signs of disease..they look great..any ideas?