Okay, so today I found an egg in my duck pen!!!! I don't know how long it had been there, so I candled it and I need some opinions as to how old it might be based on the size of the air cell. Also, how often do they lay??? Once a day?? Every 2 days??? My kid's b-day is coming up, and we're having a triple party with three cakes to include 2 other kids, and I want to know if I'll have enough duck eggs to bake three double layer cakes by Sept 27th. Each recipe call for 2-3 eggs, so since my duck's eggs are about the size of extra large chicken eggs, will I only need like 1 1/2 per recipe??? Thanks!!!! Pics: The air cell is boxed in this one.