There are 3 main types of small breed dogs.

Terriers: Fox Terrier, Yorkshire Terrier, Scottish Terrier, Jack
Russell Terrier, Cairn Terrier, West Highland White Terrier, etc.

Dachshunds: Standard and Miniature Dachshunds, also divided into longhaired, wire-haired and shorthaired Dachshunds.

Non-Sporting Toy Dogs: Bichon Frise, Miniature and Toy
Poodles, Chihuahua, Pekingese, Cavalier King Charles Spaniel, Shih Tzu, Lhasa Apso, etc.

Energetic and demanding dogs: Terriers and Dachshunds are skilled hunting dogs that have adapted well to city life, if they can get out frequently and use as much energy as they need to. The toy breeds are more suited to a sedentary lifestyle, but need careful attention, especially for their coat. Small breeds are also frequently fussy eaters. This behaviour is also accentuated by their special requirements and the fact that owners often give them treats and table scraps that may lead them to poor eating habits.

Characteristics that make all the difference: In contrast to what you might think, MINI dogs and toy dogs have very high energy requirements per unit of body weight. For example, a dog of 130 lbs. needs 3000 kcal per day, whereas a 6.5 lb. dog needs 300 kcal per day (twice as much per pound of bodyweight). Small dogs are also noted for their exceptional longevity (from 14 to 16 years) and their very small teeth. All these characteristics justify a precisely targeted food.