On ceramic eggs and the intelligence of ducks

Ceramic eggs are in existence to help chicken owners. The eggs are designed to look like real eggs and you simply place them in the location you want your chickens to lay their eggs and they take that as a cue that this is the hot new spot to lay their eggs. I mean, if the other chickens are doing it, why shouldn't they lay their eggs there as well? The ceramic eggs can also be used to discourage chickens who have decided that they should peck at and eat the eggs. Ceramic eggs are much harder to get into, and much less tasty if they do. I haven't heard a great deal about using ceramic eggs with ducks but I figure if it works for the chickens then it's bound to work for the ducks as well. Right? 

Ducks are much smarter than they typically get credit for. When last I cleaned the coop and replaced a bunch of real eggs with ceramic eggs I reasoned that the ducks would assume everything was as they left it that morning and their eggs were still safely ensconced in their nest. Gwen and Gemma, my two outdoor female ducks, did continue to use the nest and did not seem upset over the loss of any eggs (we lost a duck once when she flew away forever after her eggs were removed from her nest) so I assumed that the ceramic eggs had done their job and fooled the ducks. I was wrong. When I cleaned the coop today and went to remove the real eggs I discovered that the girls had been using their nest but every time they laid an actual egg, they would roll a ceramic egg out of the nest to make room for the new egg. By the time I came in to clean the coop the nest was full of real eggs and the ceramic ones were scattered all over the floor of the coop. How they knew the eggs were fakes I am unsure of but realize it they did. This may be why I had not heard much about using fake eggs with ducks. I am, once again, reminded not to underestimate my duck's intelligence. It seems the only one fooled when I do that is me.

The haul for today: 22 duck eggs