The neck is too long for a dog, plus, all Sight Hounds [which Wolf Hounds and Greyhounds are] have *double flexion* spines.
There would be an arch in the spine that no horse could achieve.
It’s a horse, not a dog.
[The ‘expert’, however, ~may~ be a jackass]...:)
I own a sighthound. I agree, their spines just don’t go like this. They also stretch out more when they’re running than any horse achieves. I’m a lifelong horsewoman and hound fancier; I love watching hounds whether they’re coursing or hunting. Their necks are angled differently than horses’. Their hocks are set much lower and their femurs are far longer. This just isn’t a hound; it is a horse cantering on the left lead.