I was reading the thread of people having allergies or food borne illness when eating duck eggs. Last week I ate a duck egg that I fried, after 2 eggs on different days I had nausea, each time it was worse. Then I decided it was about 3 weeks since I bought them through my farmshare so I decided to hard boil in my instant pot. Then I ate one after cooking fur 6 minutes and natural pressure release for 12 minutes then iced for 3 minutes then refrigerated right away. A few hours later maybe 2 I cracked one open and ate it with salt. About 30’ later I got stomach pains and it kept getting worse and worse until I was bent over for a few. I finally ate something and the pains went away immediately. Now I’m not allergic to anything and always eat chicken eggs with no problem so I don’t know what it is but they’re going out! My husband ate one today and he said he got minor pains in his stomach but not enough to be concerned. I did notice that after hard boiling them they got a brown circle on the shell all at one end. Anyone know why?