Andy,
I have a living hedge made mostly of Autumn Olive. I don’t actually use it to contain animals, but I imagine with a little effort it could.
I will say that my living hedge is not a simple, single row of bushes—it is at least 10’ thick at the minimum and about twice that at the thickest.
My autumn olive grows fast and is interspersed with blackberries and numerous other woody plants. Over time the hedge grows quite thick.
For the most part the
deer can get through, but I have made no attempt to control them.
If I really wanted to make it stock proof I would plant some Osage orange in there as well.
Hope this helps,
Eric