I found myself reading a blog about cocktails (I have no idea why in retrospect), and it mentioned sea-buckthorn. Since this superfruit also contains protein, it's surely a plant that somebody who plans to keep, but not feed, chickens needs to look at. So without further ado, I found the cheapest vendor of sea-buckthorn on the Japanese net, which happened to be engei.net, as far as I can be bothered to check. This berry has male and female plants and you need at least one of each, so I bought two to be going on with. I figure that if I want more of either later, I'll be able to propagate cuttings.
The sea-buckthorn grows into a big prickly shrub which should be ideal as a hedge for keeping out beagle/terrier mix dogs. With goji and and sea-buckthorn berries, I will surely corner the market in Matsuyama for healthy, organic superberries.