I would agree with what has been said and also add the influence of the other dogs. Case in point. I have a lab that as a small pup had no fear of a vacuum. A chow my wife had was scared of the same vacuum. After 2 or 3 weeks of this pup watching the older chow run from the vacuum it started to do the same. To this day 10 years later u can say ur going to get the vacuum and he hides. This same dog in the hands of my wife which is nervouse around other people will get nervouse. Take the same dog on a lead in my hand and he don't meet a stranger. I think the interactions with the other dogs could have caused the issue as well as the owners.
Shotgun
Arkansas
x2...I agree with this post as well as the previous posts...
The Chow was the dominant dog and if he is scared poop-less of that vacuum cleaner then the pup danged sure will be...I use that weapon on my pups when breaking them off of deer...I make sure to start with the alpha and make him cower at the scent and touch of deer before I move on to the subordinates...I reckon they figure pretty quick that if the alpha is terrified they for sure need to be...