Your theory works except for that part.
We have no idea how dromaeosaurs hunted, we can oly vaguely theorize. There is the popular image of a pack of dinonychus taking down a tenotosaurus, but that again is only a theory.
(Although, I can check with my friend about the deinonychus thing, there might be some reality behind that.)
There is also no fossil or substantial evidence to prove that dromaeosaurs hunted in packs. It's only a theory made into a public opinion by that piece of crap Jurassic Park that everyone seems to worship as "the one and only truth about dinosaurs".
Ahem, sorry about that. The dinosaur geek strikes again!
My theory on fuzzles: They have very simplistic digestive systems. Food is digested very fast but efficiently, which is why they crap so much (you heard what Humphrey and Irwin said about Fuzzle poo). They may have a fast metabolism to deal with food like that.