If you're looking for information about the breeds mentioned in the book, you might find it helpful to consult a James Herriot fan website or forum.
What is the breed of mrs dog roy in chapter 7 let sleeping vets lie?
Unfortunately, the breed of Mrs. Dog Roy in the book "Let Sleeping Vets Lie" by James Herriot is never explicitly stated. The book focuses more on the personalities and quirks of the animals and their owners than on specific breeds.