APPLE CIDER VINEGAR
I read both comments on the last page and feel the need to speak up...
ALL creatures pretty much benefit from ACV in their diet, whether it is a once in a while or daily type thing. It helps with gut health. In fact, it is the complete opposite of what you read or were told, Holm25. It is a treatment for sour crop, and ducks I think very rarely get it, but you would have to ask someone with more experience with ducks. Those things eat so many things, I can't imagine there is much that could plug up their system. I used to see mine eating little toads even.
BlanchRanch, it is not an antibiotic, but it is used as a preventive treatment to boost the immune system. For sour crop, it helps to neutralize the build-up of yeast, which is the component that creates the "sour" in the condition. That is why the first treatment for sour crop should be to 'vomit' out the fluids, and the next is put the bird on water with ACV for 3 days.
There is SO much misinformation on this and many other sites, so do yourselves (and I am not trying to call anyone out on this) a favor, and double and triple check EVERYTHING of any importance. There are more than one way to do many things, but when it comes to treating ailments, there are the tried and true and those complete BS answers out there. Be careful what you take for truth. Even double check what I say because I have known to be wrong once or twice, but this sour crop thing is something I have had to deal with a few times.
Also, sour crop and impacted crop are two different conditions. The cause may be the same, but an impacted crop is a much worse state of things to try fixing.