If that is so, then most likely yes. Personally, while I don't give them bull necks, they are modified just slightly. It's why they also have teeth.

I would think this is a matter of mostly artistic opinion and anatomical requirements.

Personally, I figure a gryphon has a thicker, more muscular neck and a thin feather ruff- and here is why.

It has more to do with providing an anchor for the muscles that lead down into the chest and upper back.
Not easy to have strong muscles without substantial bones to attach them to- And a gryphon needs more solid structure than a bird does due to the lion body.

So thats my take on it.


-Badger-

Well, don't they also have lion physiology as well?
I would suppose that they could have a lion sized neck if that felt like a sticking point for you...

Had to turn down my nerdy started to break out my thesaurus, dictionary and google-fu. If we assume a 100% true to life gryphon applied with the obnoxious rules of reality and logic it would likely have a more lion like neck under there. Birds have thin necks in exchange for a wide rotation radius, being able to look all around you without moving or changing your flight path just makes sense, otherwise your just waiting for something to swoop down from behind you and break your brittle boned body.

Gryphons are traditionally depicted as predators closer to a lion than a eagle as a whole, its easier to imagine them less as half and half and more like, mostly lion with a eagles head, front claws and some feathers/wings thrown on for good measure. If you REALLY want to lose some sleep, try to imagine how a real gryphon would evolve and develop if they were governed by the laws and logic of reality while at the same time trying to maintain the overall aesthetics of a fantasy gryphon.

(If we strictly applied reality however, you'd end up with a large flightless bird instead something closer to a Terror Bird, a 9 foot prehistoric death chicken.)

Gryphons have a thicker neck because that's more attractive to me.