serge:
>I don't think the problem is with ducks' food. I think the problem
>arise from the fact they use little pebbles, called grit, to crush
>their food.

Hmmm...I guess I was trying to explain WHY pellet ingestion, and not
contamination of the water or their food, is the only problem (as far
as I'm aware) - or at least the overwhelmingly important problem.

Guess I was incomplete, so thanks for expanding on my commments.

- Don Baccus, Portland OR <donb at rational.com>