I have used electric fence and the bottom wire is not electrified. Saying that you still have to have very flat ground to get them to not short out to the ground, but they still give a wack even if shorted to the ground.
I do not use it now because the foxes were jumping it and nicking my chickens, 20 in all. So I got my self a HMR and a Bull Greyhound, no not really the best way to stop the foxes is to enclose you chucks and this is what I have done.
Good luck.
Just to say the last chickens I had taken was at 11.30 am, all of my chickens were taken in the day time as they were locked a