A hinny is a hybrid of female donkey and male horse. These domesticated animals are the counterpart to the mule, which is the offspring of a female horse and a male donkey. Hinnies are generally a little smaller than mules and not quite as well-suited to being pack animals. Hinnies tend to look more like horses than donkeys, unlike most mules. Hinnies are harder to breed than mules in general, due to a discrepancy in chromosomes between the two breeds.