I have had the same horses for a while.... a palomino colt who is now 14 months and a retired barrel racing mare..she was first..palominos colt second.they have had no problems staying in the fence until recently..I adopted a pony who was severely underweight. He is 20 years old And pretty much acts like Eeyore,until he figured out How to get out of the pen. He stuck his head under tbe 6 strands of poly wire ...got zapped amd kept at it till he got out. Came home to 2 horses down the road from our house.We have a 50 mile electric fence box on 1/2 acre.for these horses. Once the pony got out...the colt got out,so we hooked up a 300 mile box which can kill small animals.we hoped it would teach them a lesson. Well.....I went outside this morning and all.3 were out..thankfully still enclosed in our yard by the perimeter fence.even the mare who stays in haystring if she thinks its hot...then she ran from me!!!! She has never ran from me.The colt charged the fence last night and destroyed it. I don't know what to do. I can't afford a board fence all the way around...and I hate to get rid of them.this getting out thing is going to cause a problem.....tips or tricks anyone?