That fence has to be AT LEAST 5 1/2ft tall or you're wasting your time. If they can get their head over it it's too short and they're liable to try and make a jump and boards will shatter. Had a cow get her head under a fence that was made of rough cut 2x6s and she swung her head up and those suckers shattered like a tooth pick. That cow is no long here but still! If they can get their head through or over the fence it won't work.