Not if you clean their cage as often as it needs, then they don’t stink as bad. Honestly, mine don’t stink at all to me. They did when I first got them, though.
Keep in mind that they’re related to skunks. They can’t help the odor!
Their tails smell like grapes, too!
PLEASE DON’T MAKE THE MISTAKE OF BATHING THEM A LOT!!!!!!!!!!
And this isn’t just an answer to the question, it’s also @Randy for telling people it’ll stink that bad. Either you’re exagrating A LOT or you were a horrible ferret owner and never cleaned the cage.