This is interesting.  When I was a child, my father had grey geese that hatched every spring.  At about 4 months of age they would get a disease that would make them appear drunk.....wobbling and stumbling.  Eventually it would get so bad that they could not walk and would in turn, die.

After years of frustrations of trying to locate and eliminate the source, he contacted the Ellington Agricultural Center in Nashville and had them test a goose.  After months of testing, they could not determine what was causing this.  All they could tell him was that it was a 'plant' that they were eating, it seemed.

Eventually my father had to get rid of all of his geese because he couldn't just let them suffer like that with no way to help them.

This article makes me wonder if it was the pond moss that could have been causing them to get sick.  To this day, I have never heard of or seen other geese or ducks getting this disease....but according to this article, it appears it may very well be the same thing.  The timing is right.......they hatch in the spring and got it at about 4 months of age....which puts it in the hot part of the summer.

Thanks for posting that.