Hi, I am not a medication expert, but from what I know, the differences are in strength. The concentration of actual medicine can vary, and that information is important because to do it right there needs to be a correspondence between weight of duck and amount of medicine. There are charts...
That looks like there may be a splinter in there. I would see if that is the case and remove that with tweezers first if there is one.
There is a method that requires no wrapping, no cutting.
I would use the foot soak and clear iodine method - worth a try - see how it goes for about ten...