Is This Guinea Pig Behavior or Sickness?

Popcorning looks like a full body twitch- they basically jump from the ground and do a weird movement with their head. It's really funny to watch and they do it very often. I guarantee this is popcorning. Don't worry so much! Try feeding the guinea pig parsley (for more vitamins) and make sure you're feeding it hay so it has proper digestion! :)