I love the owl, it has such a sweet face, for a not so easy subject you have done a great job.
Being a proportions nazi, I have to disagree with Tiny on the dog. Sorry mate I'm not a fan of that one. Though it's bold, it is just not what I like. I prefer a range of tones, so the blunt pen work doesn't do it for me, along with the proportions being out.
As for the mare, I lovethe proportions, I like the eyes though if could have been made a touch bigger and bolder. The shading is good, but as Tiny said, more detail - tonal values, tonal values, tonal values. Put in 10's, and 1's where ever you can. That is what makes a drawing pop out :)