"Ping is a Border Stack: 1/2 Border Collie, 1/4 Jack Russell Terrier, 1/4 Staffordshire Bull Terrier. She was born in Aug 2005, and is from the third litter of Border Sstacks. Ping is one of the biggest at 19 in. tall and 30 lbs. She is an easy keeper in the house—quite happy to lounge in the sun all day…but gets really revved up when it's time to play. She is very intelligent—loves to learn tricks, plays flyball and agility…. She's not a big barker, but has a large vocabulary of "Staffy" sounds."
The Border Stack is not a purebred dog. It is a cross between the Border Collie and the Jack Russell Terrier / Staffordshire Bull Terrier mix breed dog. This hybrid is being purposely bred for the sports 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 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.
Owners who use them for flyball have said, "They are perfect for flyball, as they tend to be much smaller than a Border Collie, without too much reduction in speed. They are a bit more muscular than a Border Collie, but because of the short height of the Jack Russell, they are an overall smaller dog. The fastest teams in any tournament competition are typically made up of three Border Collies and one Border Jack or Border Stack. Teams need a small, fast dog, because the height of the jumps is determined by the height of the shortest dog on the team. Therefore there is usually one short dog on the team, but because it's typically half Border Collie, it still has the drive and speed to be almost as fast as it's taller teammates. Adding Staffordshire does not seem to add much bulk to the mix. The Border Stack is said to be a bit mellower than Jack Russells and Border Collies."
"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 14-19 in. tall, 20-30 lbs. Colours vary between litters, but all have short coats."