The Border Stack is not a purebred dog. It is a cross between the Border Collie and a Jack Russell Terrier / Staffordshire Bull Terrier hybrid. This hybrid is being purposely bred for the sport of agility and flyball. They tend to be very intense, busy dogs, that need a lot of activity. Not for novice pet owners, they need an activity and a lot of daily exercise. The best way to determine the temperament of a mixed breed is to look up all breeds in the cross and know you can get any combination of any of the characteristics found in any of the breeds.
"There have been a number of litters bred of this cross for dog sports like agility and flyball. All offspring so far have been of somewhat similar build. Size ranges from 14-19in tall, 20-30 lbs. Coloursvary between litters, but all have short coats."