Hate to ask about this because it's rather gross, but I couldn't find anything when I searched keywords. My 5 week old runner duckling has some awful black diarrhea, and it reeks, almost burns my nose sort of. He seems ok otherwise, alert and acting normally. The ducklings are eating Dumor starter/grower, they're on grass and grass clippings when outside in the pen, they get small amounts of cracked corn in their food on occasion, and peas and parsley for treats. Any ideas? He had it yesterday too, not sure if it's been constant or off and on since they were outside in the run for most of the day.