Okay, so where to start. The head. The head is very odd? Ears are way too big and they do NOT have tufts like that. Ear tufts are invisible, if hardly even there at all. The eyes are too big, and the muzzle is smushed down. The cheek fur all needs to go down and with the flow of the fur. The fur overgrowth needs to go away on the eye as well.

It looks like you were trying to male them look skinny while still fluffy? They are either one or the other, as the fur will cover that up. The body is too small, the neck too big. The legs need to be shortened and brought forward a tad. Like I said before, stop the overgrowth in the fur!!! Get rid of the odd tufts on the legs. Period. The legs bent at a very awkward angle. We arent drawing horses! It's a bit less noticeable then how you made it.

The hind leg needs to be pulled back a tad, it's too round. The fur, again, needs to be taken away. I changed the angle quite a bit, to match with realistic animals.

The tail is too "fluffed out" and is way too long.

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There. I am not going to sugarcoat anything. You said constructive criticism; it's not an artistic choice when you want to improve.