Thanks to Gumpsgirl, Farrier!, silkielovr,justmeandtheflock 
and all who added to my question.  I have broken open my eggs and checked for the "bullseye", to find a very large % of fertile eggs.  After they don't hatch I don't open them.. I don't think the smell and I would do well together.. I throw them away, very carefully. 
The link w/the "bullseye" pics are great. 
I have hatched my own eggs, and had great hatches, then bought eggs, had great hatches, and 1 or 2 hatched from shipped eggs.  I just think maybe sometimes, weather changes, do affect my hatch rate, temp., humidity, post office.  I have shipped eggs, the buyers have had good hatches, bad hatches.. We never know, what happens in between.  I am sure not complaining. 
I just wanting to make sure there was not a secret to knowing if the eggs were fertile... w/o opening or putting them in the bator. 
But, I figure that is a gamble I have to take to have different lines of chickens from fellow BYC.  It is fun.  BYC'ers are awesome. And I am just trying to learn. 
M