Herdwicks are great sheep but we have never run them on the farm in Devon as they are a breed native to the Lake District really. Foot and Mouth caused the breed numbers to take a huge dip and there were concerns over loosing the breed for good.
This would have been a huge shame as they are perfectly suited to life on the hills and very hardy.
Beatrix Potter was a passionatre suporter of the breed.
http://www.peterrabbit.com/beatrixpotter/beatrixpotter2c3.cfmThey are also what is called "hefted". This means they instinctively know which farm they belong too and will always endeavour to stay on their patch of hill. Very hand as there are few fences on the hills but not so handy when you see breeding stock that will walk back home given half a chance!
Commercially they have fallen out of favour a bit as they are slow growing, but that is what makes them such good eating.
Jerry
Farmers son and one time shepherd