Cuckoo ducklings?

[duggat]

I wonder if anyone can help.
My mallard has started laying; just the 2 for now. I am thinking of replacing her eggs with some Indian runner eggs when she has laid her clutch.
Do you think this will work? She is supposed to be a good mum.
If so; when do you replace her eggs for runners?

 

[foxy]

I would wait until she starts to sit, then after a few days you can exchange the eggs. I have muscovies here and they will try to hatch golf balls given half the chance, they are trying to lay sneaky clutches all over the place at the moment.. :roll: