Hi Jim
You can buy proper electric chicken net, very small mesh at the bottom getting bigger as it gets higher. It is, as with all these things quite expensive. It's about 4' high so determined bantams will fly over it. You need to keep the grass short by regularly mowing otherwise longer grass will keep shorting it out and reduce it's effectiveness and keeping the grass short is more trouble than anything, although one lady on the PK forum uses Roundup. Having said that IMO electric netting is more useful for keeping predators out than chickens in, their feathers are an effective insulator and if something spooks them and they get tangled in it and get shocked on bare flesh and be unable to get free as they get more tangled struggling under these circumstances it would kill them. Course you could buy a roll of net and not connect it, for keeping chickens in it would probably be as effective. In fact for three weeks recently I kept my chickens out of an area of my field with non connected netting and it worked well. On the plus side it's highly flexible and fairly easily moved.
Local agricultural suppliers usually stock it and also easily available via ebay and online suppliers.
Frisbee