Quote Originally Posted by applesmom
Do all of these dogs live in the same neighborhood? Did they all die in the same manner? How old are they? Did they have known health problems? What did they all have in common?

Find the answers to these questions and any others you can think of and you should be able to figure out if it's coincidence or not.
Yup, it could just be unfortunate coincidences. I am very sad to hear about your friend's/family's dogs though, but I am sure you have nothing to be worried about.