In the movie The Hobbit, The Desolation of Smaug - the party wind up at Beorn's Hall. When Beorn is asked about other Shape-Shifters he makes reference to a past event where Azog captured the shape-shifters and tortured them for his own entertainment.
My question is - is there any mention in the Hobbit, LoTR, Silmarillion or other letters for the extinction of the Shapeshifters?