There may be many reasons for dogs to be born with deformities. Here are some common factors:

Genetic factors: Certain genetic mutations or genetic defects can cause deformities in dogs. Inherited diseases or genetic abnormalities may be passed on to offspring during reproduction.

Maternal health: The health of the mother during pregnancy is crucial to the development of the embryo. Infection, disease, malnutrition or exposure to harmful substances may affect the normal development of the fetus.

Environmental factors: Dogs exposed to certain environmental pollutants, chemicals or radiation during pregnancy may cause damage to the embryo.

Nutritional issues: The mother’s body lacks necessary nutrients, such as vitamins, minerals, etc., which may affect the normal development of the embryo.