The possible duck egg is the off white/dirty one:

It would possibly be from a young Cayuga duck. The eggs are never in the elevated nest box, often outside near the duck pool on the ground. Always that weird color, been going on for over a month, and I set 6 of them, one was fertile and looked to be doing great till no movement at lockdown candling.
It would possibly be from a young Cayuga duck. The eggs are never in the elevated nest box, often outside near the duck pool on the ground. Always that weird color, been going on for over a month, and I set 6 of them, one was fertile and looked to be doing great till no movement at lockdown candling.