The Screaming Sheep- Real or Fake?

This video is creepy and funny at the same time. There is also a big debate on youtube on whether or not this video is fake. Its hard to tell. I have heard some sheep make some crazy noises before, so it is possible?   Or it could just be someone with way too much time on their hands that likes to dub over animal videos.

Also, do you think the Doritos Super Bowl commercial was inspired by this?