We have a Mallard that I have caught in the chickens nesting boxes a couple times lately. I'm pretty sure that is going to end up where she will lay (she is 17 weeks) and I really will have no idea it is chicken or duck egg. We gave her a nest on the ground, but she never goes in it, and prefers the nests that are 2ft off the ground. How will a duck egg look compared to a chicken egg. We have chickens that lay everything from chocolate to blue. From tiny to extra jumbo.