Chicken Knox, which seemed to work, was 6' high chain link fence, dug into the ground for 9"-1'. Three strands of electric, one as low to the ground as you can get away with without the grass keep shorting it out, one about 9" above that, and the third near the very top, to stop 'em climbing over.
If you keep the grass short so it doesn't short the current, a charged battery should last a good long while.