James,
Due to flood damage, and as we are getting a couple of Dexter cows, we are having to replace and upgrade some of our fences, so I'm copying this idea from an alpaca stud farm.
Basically, we are building two parallel fences, 4'6" high and 2' apart. Each fence supports a mesh of heavy duty chicken wire. Because the chicken wire is 4' high, there is a 6" clearance between its lower edge and the ground. (This is to prevent the mesh from rusting, as it would do if in contact with the ground.)
Between the two fences, tagasate will be planted, close enough together to form a dense hedge. As the plant grows, and protudes through the mesh, it is grazed by the critters. (Alpacas can also graze the tops between the two fences, which encourages a denser growth.) When the plant is growing a bit above the top of the fence, it is trimmed flat, and a 2' wide strip of mesh is wired across the top, effectively boxing it in. Thereafter you can leave it to the animals to keep your hedge/fence looking like those of a well manicured English estate. (....with alpacas?)
This type of fence does not encourage animals to force their way through, and also forms a good wind-break, with some shade. Mind you, it wouldn't be easy to move it in a hurry, so you'd have to plan carefully where you want to build one.
Shin