"says we should've imprint-trained him"

Imprint training means working with newborn foals to mould their personalities. It is claimed that this can ease handling, enhance later training efforts and reduce injuries. Imprinted foals are thought to see humans as horses, not predators.

During imprint training, the foal cannot escape exposure to frightening stimuli. As a result, it becomes dependent and submissive in its attitude. The foal sees the trainer as a dominant horse or herd leader.  It becomes desensitised to most sensory stimuli (visual, auditory, tactile, and olfactory), responding only to those stimuli used as aids.