No, the ponies are animated using 2D puppets, more like a video game character or something than a traditionally drawn animation. Or why not an actual puppet/action figure.
The same body parts are reused over and over and over again and bent and moved around, and things like a pony talking is done by keeping the head stable, and replacing the mouth part with I think 4 standardized mouth parts plus numerous special ones for gasps and shouting and what have you.
Mouths, eyes, tails, limb positioning and similar vary a lot, because they use a lot of different parts for those, and they get dragged around a lot. It's only by accident that ponies' ears sometimes remain at a roughly similar -height- above the hooves when the head bends forwards and backwards some of the time. This is like comparing your Batman toys' heights while standing straight, to the same toy bending his head forward and with legs slightly ajar. It's a fairly poor measure because you'll very rarely manage to get the entire figure standing exactly the same.
(Folded) wings, ears and horns on the other hand use basically only one model, come in one variant that never changes, and are always attached to the body. Because OF laziness and cutting corners, these elements will (almost) always remain the same size. On your batman figure, this would be eyes, bat-ears, and what have you, things that are easy to measure and don't change regardless of Batman's position, even if he's kneeling or sitting.
THEN the entire puppet can be scaled (to make it appear further back/closer to the screen), and here the animators do cut corners. Because it's 2D it's not an exact science, and ponies do vary in size from scene to scene, while the body proportions stay exactly the same.
On top of THAT, tweaking can be applied, "stretching" parts of the model to make it seem more alive, and this does fuck up body proportions. It's commonly applied to the face, mane, tail and limbs, rarely to wings, and never horns.