What happens with Chihuahua incestuous breeding?

Direct (lineage) breeding of Chihuahuas is not advised, because inbreeding raises risks of hereditary disease and fetal deformity, plus organ underdevelopment, stillbirth, premature birth, malocclusion, weak immunity, and shorter life.

For breeding, go to a pet shop or kennel to find a good-looking, healthy male. Though it costs time and money, it ensures healthy puppies.