I think it is a rare drop (maybe in only certian quest not sure).

http://dfwiki.com/index.php?title=Main_Page
so u may know where to find it

you need to have a dragon amulet and buy dragon coins whith it and then go to sunbreeze
groove but YOU MUST HAVE A EGG OR DRAGON and if you don you cant get super dragon chow !!
if you dont have a egg go to the sighn that say this way then go to the valince and do a
dragon quest for five eggs fist go to sevil dumpsite