Well, I don't know which foods smell worse than others, but I feed my guys Mazuri ferret food, and their poo smell is manageable. I think Totally Ferret (which is a great food), produces some pretty stinky poo, but I could be wrong.
Cat food in generally is pretty stinky, I think.
I'm completely guessing on all of this though, so if someone knows differently, speak up!

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"Dogs are followers, cats are self-absorbed, ferrets just are."