Deformed dog breeds are usually the result of humans inappropriately breeding and nurturing dogs to meet specific aesthetic or functional needs. Here are some common dog breeds that may be considered deformed by breeding:

Bull Terrier: This breed may have been bred to emphasize its specific head shape and facial features, which can sometimes result in Structural anomalies.

English and French Bulldogs: These breeds are often loved for their short, broad heads and prominent facial features, which may also increase the risk of respiratory and skin problems.

Teacup Dog: The Teacup Dog is an extremely small breed whose breeding may involve dietary restriction and the use of growth inhibitors, leading to structural abnormalities and a variety of health problems.

Please note that not all of these dog breeds have deformity problems, but some of them may be due to inappropriate Deformed characteristics due to the way they were raised. At the same time, deformities are not only found in the above-mentioned dog breeds, other dog breeds may also have similar problems due to inappropriate breeding methods.