Sitting on eggs

Usually when I see a chicken sitting on eggs feeling broody I panic, and want her off so that we can use the eggs, and have no rescue attempts of chicks. However, when I wandered past the duck house the other day something caught my attention. The eggs that are positioned neatly in the corner, had someone sat on them, however, it wasn't Nellie or Lucy.

It was a bloody chicken, who had decided that in her wisdom she was going to sit on the eggs. Now this puzzled me for  a moment, is it possible for chickens to hatch ducklings, or would they very quickly realise that their babies were in fact not theirs. if we allow this crazy chicken to remain on the eggs, what will happen?

So, I Googled, and apparently people have let their chickens hatch the ducklings, which seemed to be a success. Until, the small matter of the fact that ducks swim and chickens don't. This in my mind is a rather large issue, and could cause problems when the batch of ducklings want to take a little dip. Will mum chicken stand on the edge guiding the ducklings, or will she at this point think her brood are completely insane and give up on them completely.

With this in mind, I do not know whether to leave the eggs and hope that one of the ducks will decide that they do in fact want to sit on them, leave the insane chicken, and see what happens, or take the eggs and make a cake...decisions, decisions.....