I was considering solar powered electric wire along the inside, since I plan on dividing it up a bit anyway to rotate the animals. Also, as I mentioned to another reply: Considering planting Osage Orange along it in some years and letting a living fence swallow it up near the end of its lifespan to replace it.

Thanks for the input (as always, honestly - some days I need all the advice that I can get) and for the encouragement!