We have a Russell terrier, also known as an Irish Jack. Our dog has loads of energy but I wouldn’t call him hyper. He’s four now, and mellowing a bit into his adulthood. He’s a wonderful, wonderful little dog - about 11 inches at the withers and 14 pounds of pure muscle. He can jump and run like nobody’s business and is the perfect size to be portable and easy to carry, if you need to. I don’t like little dogs but we needed one for our then-10 year old son…a Russell terrier is a big dog in a little dog’s suit.
I’ve known a couple Jack Russell terriers, which are the taller, leggier type, and they were indeed some high strung, hyper individuals. Our Russell terrier is high energy, always ready to go do something, whether it’s play tug, do barn chores or ride to the post office in the truck, but will also settle right down and loves snuggling in bed or on the couch. He’s a terrific companion for our son.
He has never ever met a stranger and is waggy-waggy friendly to every human or animal he meets…except for vermin.
It took him a long time to housebreak but once he got it down, he’s never made another mistake in the house.
Another thing: his nose will take him places. He’s got a great nose and if we’re out with him on a ranch and he’s unleashed, or if he walks through an open gate at home, he’ll start following a trail that may take him away for hours…and he doesn’t necessarily know how to get back home.
We’ve taught him that our cats and our chickens are to be left alone and he respects that. (It helped to have a confident cat.) We take him everywhere we can and he’s just adored by our friends and family.
Even in a litter of terriers, there’s going to be some that are high drive and high energy and those that will be milder. I say talk to breeders and indicate the personality/drive type you’d like and see how they steer you.
Hope that helps!