Yes. Or that there's a picture of a duck on an egg. Same as the English sentence :P
To get exactly on top of one would say oven på.
I would take this to mean a duck sitting on an egg to incubate it the same way a chicken does.
Could this also mean 'a duck for an egg', as in trading the duck for an egg?
No, that would be "en and for et æg". And that better be a golden egg or you just got screwed.