My guess, they were poisoned...the stables are not too far from where my parents live...the american horses are very well taken care of...but these poor horses came from Venezuela...I suspect they're not taken care of as well.
Then again, I hear even american race horses are euthanized if they do poorly in a race.....it's all about money...and if the horses don't produce, they're expendable....it's SICK and a tragedy.