I didn't realize this:
ACVS - Cleft Palate
Risk Factors:
Purebred dogs and cats have a higher incidence of cleft palate, and brachycephalic breeds, with their short stubby faces, are most commonly affected (Figure 3). Cleft palates may occur more commonly in Boston terriers, Pekingese, bulldogs, miniature schnauzers, beagles, cocker spaniels, dachshunds, and Siamese cats.
Although heredity is considered the primary cause of this problem, nutritional deficiencies, viruses, and poisons that affect the mother during pregnancy may also increase the risk of cleft palates in developing puppies and kittens.