Duck romance yet eggs still infertile... why?

[ChickBond 007]

My ducks have become quite "romantic" since spring began. They are 7 months old now. One hen is laying one egg per day (at least I think it is only one hen), and each day we take the egg, label it, and put it in the incubator. Every one has been infertile by day 10 candling.
Now, I've tried to "set the mood" with a baby pool full of water 9" deep and also a shallow pan of 2" water (which they prefer for romantic interludes). They're eating well, quacky and happy.
Why are we still getting infertile eggs? Do I need candles and caviar? LOL

 

[RooptyDoo]

I have the same problem except it is with chickens.

 

[ChickBond 007]

Did you use candles and chick-mash? LOL

 

[goosedragon]

The drakes often mature slower than the ducks. yours are all fairly young yet.

 

[Wifezilla]

GD is right...you just may need more time. Also, how fluffy is the female's vent area? Too many feathers could be blocking things maybe?