I regularly use electric to direct the sheep to where we want them to graze/to rest areas/to divide paddocks, etc and it works really well BUT I do use 5 lines of (tight, undamaged) fencing with a very powerful fencer, keep the battery well charged and have the earth stake a good 2 feet into the ground. It pays to mow a path where you'll put the fencing to reduce the likelihood of it shorting out on long grass, and also reduces the temptation for the sheep to try and put the heads under the fence to reach long grass on the other side.