At first glance these horses appear to be acting goofy.  However, the culprit for the resulting, interesting look is the large group of flies just above the heads of the horses.  I apparently caught in a pic the final stages of the horses shaking their heads to relieve themselves of the flies.  The horse to the right is still finishing up the head shake...the other two are still slightly in motion verified by looking at the arrangement of their ears.  Pic taken in June 2018.