eggs not fertilized despite mating

[OrganicVanek]

My Muscovy just started laying eggs and we cracked open the first five and are going to let her sit on the rest and {hopefully} hatch little babies. However, when we cracked open the eggs they appeared to NOT be fertilized. How can this be? There has been PLENTY of mating going on!
I did read this: "

The males often try to force copulation, but the complex mating geometry allows the females to retain control—most of the forced copulations do not result in successful fertilization."
from this link: ​

http://www.southfloridamuscovyducks.com/courtship-and-reproduction.html
Has anyone else experienced mating ducks not being successful in fertilizing the eggs?

 

[Finny]

How old are your ducks? I have heard young males may need more experience in order to properly fertilize eggs.

 

[OrganicVanek]

they are 11 months old. So still a little young

 

[MIster Ducker]

That may be it...

 

[Richb353]

Maybe they need some more Barry White or Marvin Gaye?

Sorry, couldn't help myself.

Rich