Those horses are feral, not wild. They descended from purely domesticated animals. A truly wild animal that's trained (such big cats, primates and etc.) is "tamed" not "domesticated". Domestication requires many years (decades to centuries depending on the species) of selective breeding of an entire population, not individuals, to alter appearance and behavior. The trailer clearly shows the raptors are tamed, but not domesticated. Also keep in mind that a tame animal still has attributes of it's wild ancestor and potentially aggressive (an aspect the trailer makes very evident is the case for the raptors).