Duck Egg Size

[Senna95]

I had one of my pekins lay a quadruple-yolker last year! Should have gotten a picture of it, but I thought it was just a goose egg (a very long and narrow one).

 

[DB_Tex]

I can confirm that campbells, welsh, swedish, golden 300, buff and cayuga eggs all fit into traditional cartons. Just barely.
(Had a crabby old man knock my duck eggs size because of it though. He was just looking for any excuse to rag on my 5$ price tag.)

 

[learycow]

I agree that most medium sized ducks (khakis, harlequins, buff, swedish etc) lay eggs that will fit in a large-extra large carton. However, my pekins, not quite a year old now, are laying GIGANTIC eggs. They only fit in a jumbo carton, and sometimes even that is a tight squeeze!
I also agree that your young hens will lay odd sized eggs for a while before they get it straightened out. My khakis laid the most double and triple yolkers I've ever seen! Out of 6 hens, I got 2 every day for about 2 months! (this was last spring).
I have 2 groups of khakis now. The younger ones lay regular sized eggs that will fit in a normal egg carton, but my older khakis lay huge eggs like the pekins. These only fit in jumbo sized cartons which are a pain to find around here unless I order some online.