These are GOOD. They are the best you have done so far.
I like the full body one quite a lot. Everything from the shoulder back ward if perfect. I can really see the shape of the bones, under the skin, demonstrated by the shine and shadow. They horse seems to have weight and exist in space and be affected by gravity.
However, when you get to the mane, this gets lost. The mane doesn't have the feel of "hanging". Mane is affected by wind and gravity. It looks kind of "bushy". Maybe this horse WAS bushy maned, I dont' know. Also , the mane obscures the topline of the neck, but somehow it doesnt' seem quite right, maybe a little bit overcurved? not sure. The neck is a tiny bit small compared to the rear. This is total nitpicking, but you have asked me to give you my feedback.
I like the way the feet kind of dissolve away. It's more artistic and I always like it when the artist lets me, the viewer, fill in some of the blanks.
The body is a tad short. Really , the hip and legs are terrific, textbook perfect.
The headshot is good, but I find it less appealing than the full body. There's a kind of stiffness about it. even leather tack can have softness and "drape" as it goes around the nose. It might have a little twist to it, or the roundness might collaps a little at some point. All these help to define it as existing in real space. the bit comes off really well and it really looks like it has some pressure on the horse's lips. You might give it even more reality if it had some shine to it (being stainless steel, it may have a "shine spot" where the light is brightly reflected).
The eyes are well situated in the skull, balanced from each other side to side . If you can have a tiny "shine spot" in the eye it helps to give them life. I sometimes add one, even if it wasn't evident in the photo.
YOu are progressing nicely. as you get more confident you will not need to have the pencil so smeared to achieve soft looks. It's nice to have soft looks, and you do it wonderfully to get the shine and muscle down perfectly. But you want to have it balanced by areas that are really crisp. If it's all soft the overall feeling is mushy. You lose the whites and don't have any real darks.
What kind of pencil are you using?
Just for hey of it, can you get some black paper and use a white conte pencil?
Maybe for a birthday gift you could ask for a gift certificate to the local art store and get some neat paper and colored pencils
Your work is starting to leave the childish look and really grow up!