Huh, come to think of it, the ducks probably weren't the only ones affected. We used the same corn (the mold-suspect ingredient) for all of our animals, and had some interesting coincidences. Namely, all the ducks stopped laying, the hens (sixteen or so) went down to an egg or two a day, and the dairy goats dried up a whole lot faster than they should have.
I think it's most commonly Aspergillus that it found in corn ... and, it can be a serious problem, long after the grain's gone. And, if it isn't? It can be checked, and you could possibly test the containers, or even the crops of other live birds. Here's the USDA's guidebook on aflatoxins in grain.
The following links are from the Merck Vet Manual ...
Aflatoxicosis
Fusariotoxicosis
Ochratoxicosis
Ergotism
Citrinin Mycotoxicosis
Oosporein Mycotoxicosis
Cyclopiazonic Acid
Sterigmatocystin
Diagnosis
Treatment
Prevention
As to the potentials for your other livestock, and as additional resources:
Cornell ... http://www.ansci.cornell.edu/plants/toxicagents/aflatoxin/aflatoxin.html
Ohio State ... http://beef.osu.edu/library/mycotoxins.html