My two Adult Dogs are strictly Carnivores. If I try to give them a Carrot or bit of Green Been, they push it back with their noses, and sit there looking up at me like I was trying to poison them.
However, My Pup Ichabod will absolutely eat anything ! I think if I were to sprinkle a little salt on a Nail, he'd gobble it up.
They all eat their Dry Food without any hesitation.