Are Jack Russells hard to house-train?

Yes, they are often very difficult to house-train. They require a lot of patience as well as positive reinforcement like food or play to convince them they should go to the bathroom outside the house and not in it. The reason for this is that they simply march to their own drummer. A Jack
Russell sees no reason to hold his urine or feces for when he’s outdoors. Why not go in the house where it’s most convenient? The fact that his owner doesn’t appreciate soiled carpeting or a pile of poop in the living room doesn’t really matter much to the typical Jack Russell Terrier.

In order to get a Jack Russell to see the wisdom of pottying outside, owners have to use a lot of rewards. Eventually, the Jack Russell will decide that going to the bathroom outdoors is more beneficial than doing it inside, because treats and/or play results when he does his business in
the yard instead of in the house. In time, going potty outdoors will simply become a habit.

How big do Jack Russells get?
Jack Russells vary a lot in size, depending on the type of Jack Russell. The smallest members of the breed stand only about 10 inches at the shoulder.

The largest Jack Russells measure around 15 inches high. Small Jack Russells can weigh as little as 10 pounds, while larger individuals reach 15 pounds.