There are several theories on why a horse enjoys the gulping in of air and grunting that are synonymous with cribbing.
Most experts agree that boredom increases the likelihood of cribbing behavior.
However, all horses are bored at one time or another, so boredom seems only a catalyst. OCD is not fully understood, however it appears to be a phenomenon of the modern man . . . Both over and under-stimulation can be stressful. Stress appears to play a major role in the development of Obsessive-Compulsive type behaviors such as cribbing. The extreme pleasure, and aleviation of stress that a horse experiences while cribbing is often at the risk of your valuable property, and his good health.