Primitives, and probably many other breeds eat mixed sward, including nettles, not brambles, many trees and bark. They love plants such as cow parsley, brassicas, mixed hedgerows, willow, nettles when they are old and the grass has stopped growing, thistles (breeds such as Shetland will eat spear thistles which looks terrifying but they make sure the spikes are facing in the right direction) . So, dorpers are not unique, except perhaps that they left your hedge alone......