I have been having a continuous problem with my duck eggs having blood in them, I get them fairly often. It is usually quite a bit of blood and some other material ranging from a long thing, like in the photo below, to a small roundish thing. While the eggs are probably fertile, they are not left more than an hour or so before being refrigerated, as the ducks stay in a small area at night, and I collect the eggs first thing in the morning. There is nowhere for an egg to be hidden, and they're not being layed later in the day. In the picture the white of the egg is just missing because I scooped it out of a pot of water, and the white didn't make it out with the rest of the egg, there was some more blood throughout the white in that side of the egg. I am mostly concerned because I sell the eggs, and if I miss them in candling I don't want to gross out or lose my customer. I would really like to know what is causing this and how to prevent it, if anyone happens to know? It is fairly hard to see while candling it, but I think I need to get a better candler, which would help too, but still it would be great to know the cause.