I have a Rat Terrier – very similar in looks to a Jack Russell but the ears in 95% stand straight up – mine is all black with just a little bit of white (not your usual Rat Terrier coloring.) Ratties are supposed to be a bit more laid back than Jack Russells but not by a bunch.
I had already installed the electric fence in the yard for my Springer so I thought we’d give him a try with it as well. My Springer is so laid back that I could have the fence on “beep only” and she’d never venture outside it. My Rattie is on the huge side for his breed (breeder told me 15 lbs tops and he weighs 25 lbs at 1.5 yo – apparently his grandpa was a big boy too.)
I got my “little” guy the same voltage color as my Springer (she’s only about 10 lbs bigger than he is --small for her breed.)
No biggie for my little Rattie – I could see him shudder as he broke through the fence line but over he went.
Now he has a collar that would stop a Rottie. It’s almost as big as his head. But it works.
There are some fences that allow you to adjust the voltage and if you can find one of those, I’d say try that. Mine doesn’t allow that so my only choice was to up the voltage on the collar.
I thought about a regular fence but Ratties are great diggers and great jumpers and it would have to be one high fence buried deep in the ground to keep my guy around. Plus dh was dead set against fencing in his beautiful yard.
I know there are breeds that defy most electric fences but I think within reason and decent training you can find a solution.
(just so you know, the collar in that pic is the small one.)