I have quite a few comments, so I'll leave most of them for either tonight or email them to you. Here are my overall impressions:
I like the story so far. You're setting up some good conflicts. I like the first scene, running to the pasture. Gets you right into the action. Pacing is good--something keeps happening, but not too much that'll overwhelm a reader, and you don't linger too long on each scene.
It does need more show and less tell, especially in telling the background. Maybe details the two paragraphs of background at the very beginning can be introduced little by little as reference to them is needed--such as when Birge tells Peks that his foot is as ugly as the girl they tease, adding the detail that she was the daughter of the Laird that they teased would be appropriate. The reasons why they tease her can be brought up in other situations, maybe inserting a teasing scene with the girl, who asks them why they tease, or whatever.
The bullies do seem menacing, and I'm assuming you'll flesh them out more later on in the book.
I'm also assuming you'll address the boys' obvious misogyny at some point in the book (either because it's part of the society or because they have personal reasons), or the two references to women's taletelling would be superfluous. I could see you bringing in references to crones and old wives' tales with this. Both boys seem to genuinely care about their mothers and respect them (or at least Peks does his) and it seems you're setting up a dichotomy. Is this right?
Dialect: sometimes the "ya"s make me feel like they're talking in an exaggerated Canadian accent. Can you add other marker words to give the lilt of the accent, at least at first? There are a couple places where you do this in sentence structure, but I think it could be reinforced a little more. Also, you'll probably want to distinguish between possessive "yer" and the contraction for "you are." I would suggest always using "you're" for the contraction, for ease in understanding. I, at least, usually read "you're" as "yer" pronounced anyway. It might make reading the dialect easier. Also--do the high-born and low-born speak in the same dialect? You have the laird speaking in the same dialect, and I just wanted to check if that's what you intended, especially because the thugs don't seem to.
There are also a couple of things I wondered whether you might want to use. "Hi," "shape up," and things like that seem to be very modern phrases, and if you're setting this in a medieval world, you might want to go for more medieval-sounding idioms. Also, since you're telling the story from Peks's viewpoint and he is low-born, you might want to watch out for some of the more sophisticated words you use when describing their thoughts. Then again, he's a smart kid, so I don't know.
Watch out for passive voice. There are many places where you can say the same thing in half as many words. I realize this is an early draft, but I have some suggestions that I've marked as I read that I can email to you.
Also watch out for really long sentences. They're not technically run-ons, but sometimes the subjects seem unrelated (also noted in the file) and might work better as separate sentences.
One last thing--I usually think of a thicket as a stand of trees, not very large--maybe ten trees standing close together (thick). Is this your intention? You also refer to it as a wood, which in my imagination is much larger than a thicket.
Most of these things are details rather than overall. I think you've got a great start here and can't wait to see what happens next. The overall story arc looks to be fascinating.
