I advertise early in the spring, on craigslist or free-cycle and have been lucky to buy fresh goose eggs and turkey eggs(as you see here).  You can negotiate with the seller what price you will pay for a dozen eggs.  Once you have established the contact, it is easy to make arrangements year after year, for purchasing their eggs.  
 IMPORTANT: I ask the sellers to simply rinse and store the eggs in the fridge until I arrive.  One time a seller scrubbed the eggs clean with a Brillo pad!  This could damage the cuticle of the egg and scratch the surface, spoiling it.  So a gentle note to the seller is all that is needed. 
DISCLAIMER:  AS ALWAYS BE CAREFUL/CAUTIOUS WHEN BUYING OR TRADING ITEMS FROM CRAIGSLIST!  

I prefer to use fresh eggs when I am writing pysanky, because they sink in the aniline dyes.  Ready-blown eggs will float, and need to be submerged with a shot glass, or a heavy spoon.  This can cause un-even dying, and worse, marks on the dyed egg.  Because I take so much time to measure out the designs, I do not want to ruin the pysanka with spotty, marked or un-even colors. 
I advertise early in the spring, on craigslist or free-cycle and have been lucky to buy fresh goose eggs(as you see here) and turkey eggs, from under an hour away from my home.  You can negotiate with the seller what price you will pay for a dozen eggs.  Once you have established the contact, it is easy to make arrangements year after year for purchasing their unwanted eggs. 
I also buy fresh "double-yolk" chicken eggs from the local Amish market; and I have purchased ostrich eggs from a local farm auction. 
I ask the sellers to simply rinse and store the eggs in the fridge until I arrive.  One time a seller scrubbed the eggs clean with a brillo pad!  This could damage the cuticle of the egg and scratch the surface, spoiling it.  So a gentle note to the seller is all that is needed. 
DISCLAIMER:  AS ALWAYS BE CAREFUL/CAUTIOUS WHEN BUYING OR TRADING ITEMS FROM CRAIGSLIST!