Why should an owner not assume a Kooikerhondje only needs minimal exercise based on its small size?

Answer

Because they possess the stamina of a sporting breed and require vigorous daily activity

Although small, the Kooikerhondje has the stamina associated with a sporting breed and requires daily vigorous physical activity along with mental engagement to prevent boredom.

Why should an owner not assume a Kooikerhondje only needs minimal exercise based on its small size?
animalDogusebreedKooikerhondje