My duck eggs are various sizes but even the double yolkers will fit. Unless you have Muscovies they are probably quite large.
Couldnt tell you where to find them we have a recycle place that carries egg cartons toilet paper tubes and just about anything you want. Are you selling them?

Am I selling them?
I hope to. The girls are just starting to lay and right now I'm getting 3 eggs a day providing none get broken, which occasionaly happens. I've got a good laying breed and I hope to increase production soon. I need to get more hens if I want to really tackle duck-egg sales, providing there's a local market. Do you know anything about selling duck eggs?

Not really this is all I know. They sell for 12 dollars a dozen.A buck an egg. They are better for people with cancer than chicken eggs. The only places I have seen them for sale is the internet and a local organic farm.
I have thought of bartering them on craigs list. You might also try sending your info along with how great they are for baking to some local bakeries or chefs.It would be easier to sell them to someone who buys them all then to try the neighbor thing.I have found that even giving them away people turn their noses up at the thought. I had that happen at church until I told them that all the items I had brought for brunches were made with duck eggs and they never knew the difference! Happy quacking!