Simplify the following text for a Grade 7 native English-speaking person.
Original: Some Toy Fox Terrier breeders can trace their dogsâ lineage back to a Smooth Fox Terrier called `` Foiler '' , the first fox terrier registered by the Kennel Club in Britain , circa 1875-76 . It is believed that careful breeding from smaller Smooth Fox Terriers without crosses to other toy breeds such as Manchester Terrier and Chihuahua resulted in the Toy Fox Terrier of today .
Simplified: The Toy Fox Terrier ( also known as American Toy Terrier , Amertoy ) is a small terrier breed of dogs .