The definition of loose impediment specifically lists dung as a loose impediment. I think you are in Rule 23 territory. If the stuff is fresh and thus adhering to the ball, it isn’t a loose impediment and you cannot touch it at all.
My home club in Wales had a local rule specifically for this situation. If your ball came to rest in something fresh, you got a free drop. And as our course was on commons land, we had a lot of these situations to deal with.
But if there's no local rule at the course you're playing, then the rules provide no relief and it's a really bad break. Either hit it out of the shit (literally) or take an unplayable.
A few years ago I played Holywell in North Wales which is also on common land and populated by sheep who deposit lots of loose impediments. I hit one of the sheep first bounce with a drive - it just stood there after it had been hit looking mildly affronted. However, as I'm a vegetarian, friend of the earth, tree-hugging eco-warrior I've felt guilty ever since.
A few years ago I played Holywell in North Wales which is also on common land and populated by sheep who deposit lots of loose impediments. I hit one of the sheep first bounce with a drive - it just stood there after it had been hit looking mildly affronted. However, as I'm a vegetarian, friend of the earth, tree-hugging eco-warrior I've felt guilty ever since.