I have ducks and usually I get nice eggs from them however I have seen 2 lately that appeared to have what looked like a bit of poop in the egg yolk. I say poop because it appears to be greenish grey and looks a lot like a bit of mostly digested grass. My girls do free range during the day and eat a lot of grass and the spots really did look like their grassy poop. The spots do not look anything like blood spots or meat spots, which I have seen many times in the past. The stuff is on the inside surface of the yolk. The 2 eggs came from separate ducks (different duck breeds and different shell colors/size makes me certain). Everyone seems fairly healthy although I have seen one of the girls sneeze a few times lately and it was one of the ones that laid one of the eggs with the poop? spot. Also (unrelated I think) I have had one girl who for many months now does not lay a shell on her eggs (she laid good eggs for over a year before switching to shell-less and membrane-less eggs). She is now back to laying eggs with a membrane. Other then that everyone seems normal. Eating, drinking, splashing/swimming, pooping, laying and running around, etc all seem to be normal. Anyone every hear of something like this? Any idea on what might cause it? As I understand the yolk is formed pretty high up and should not be contaminated by poop under normal conditions. Any diseases that cause weird eggs like this?