We have a 2 year old jack russell; he is awesome. A couple of times he had a strange behaviour that I do not know what causes it. Suddenly he will look scared, try to hide behind me and change place every 5 seconds like he doesn't where to put himself. He is not physically sick and go away the same day but I don't know how to prevent it or how to deal with it. Does anyone else experience something like that? Thank you