I don't want to start a ruckus but, yes, in the Harry Potter books,
ferrets were fed to the griffins.  J.K. Rowling also had one of the
characters turn another into a ferret and bounced him off the walls at
Hogwarts.  They were major passages in the books, so if the movie stays
true to the books, then they'd have the scenes in it.
 
This doesn't mean that ya'll should boycott the movie just because Ms.
Rowlings has no love for ferrets...just that you should be aware that
some scenes might be unsettling to us ferrety people.
[Posted in FML issue 4551]