Many horse owners prefer barley over oats because the former is less likely to trigger "hot" behaviour.
A common alternative to oats is barley. One advantage is that it is less likely to result in excessive energy. However, horses typically prefer the taste of other grains and some horses are reluctant to eat barley due to the taste.
Barley starch is also more difficult to digest and consequently more of it passes through the foregut to the hindgut, which may increase the risk of colic or laminitis.
Barley grains are relatively hard, so they typically need to be crushed