for horses that run thru electric, if that is your main
fencing/perimeter fencing or even if you use it for separating pastures, I
can't recommend Horse Guard fencing highly enough. It puts a stop to the
toughest horses when installed correctly (with tension). I have a smaller
temporary pasture that I use other electric on (string or a weaker strand of
Horse Guard not attached to permanent fencing), but only put my gentle/older
horses out there. Horse Guard also sells a fence tape that doesn't require
grounding. The horses totally respect Horse Guard and even when it's not on,
they will stay away from it.
PS. for a horse breaking thru fencing, she may not be
getting shocked. she might be scuttling under before it shocks her. I had a mare
do this a few times, going thru a string fence I had set up to keep them away
from the backside of my barn. I watched her do it TWICE, without getting
shocked. Then I took her in a halter and held the electric handle out and
shocked her with it, just to be sure she understood that that area was electric.
I don't know who got shocked worse, me or her! but she respected it after
that.