It's odd, I didn't even realise there was a deliberate rhyme until near the end. I think, personally, this would read better in stanzas, with a break after "just thirst to go far," and "and they only go where they're told," and "and never look back." Just a thought. Besides that, really enjoyed this, the imagery is natural and thought-provoking. I especially liked the "cantangerous colts," ace alliteration. Nice work.

Good metaphor.
This is great. :D
I like seeing truth in poem form.