I hope that he recovers. If you have others that have botulism use the activated charcoal with them according to the directions in the link I gave you.
thanks for updating and please let us know how he is doing. :hugs
Here is the number for Duck Haven in S Florida in case you might want to ask for help close by This is a Muscovy rescue center and might be able to help with meds if it's not feasible to get to a vet.
954 979 5044
Yes leave it ,depending on what you are using the link I gave you tells you how long they should have the flush.
@Gindi what part of the world are you in?
Could be botulism do they free range where they may have gotten into something toxic? Are they able to hold up their heads?
https://www.backyardchickens.com/threads/flushes-for-aiding-in-toxin-removal.70052
Any discharge from eyes or nares listen to breathing does she sound congested?