Kylie Jenner: Skinny Greyhounds Are Okay ... Dog Org. Sign Off

All the haters calling out Kylie Jenner for animal cruelty are barking up the wrong tree ... this according to no less an authority than the Italian Greyhound Club of America.

Experts with the club tell us the video Kylie posted of one of her pups is perfectly normal for the breed ... despite the flood of people accusing her of being a crappy pet owner.

A spokesperson for the Club says the pups are supposed to be lean, since they're bred for running -- and, in fact, a healthy Italian greyhound should show a hint of 3 ribs and its hip bones.

The IGCA rep also points out the still photo from Kylie's video could be misleading ... since the dog could be taking a big breath which would exaggerate the rib cage.