There are a dozen goats or so in the mix to take care of the really tough stuff that the sheep won't touch.
They stay in each spot for a day or two, and are they moved to the next by the shepherd and his dog. They are kept in place with a solar-powered electric fence. Finally, the flock has gotten close to our house. We went out twice yesterday to watch them. I had no idea what loud eaters they are, quite the noisy group. Here are a few photos from the outing.
The SF Chronicle actually did an extensive article on the whole operation in 2005. Here is the link if you want to read more.
Real time map of where the sheep are can be found here.