Hen lays unfertile eggs, will they ever change??

[DutchChicky]

Our pretty little Spangled Hamburg hen lays very nice eggs for the last 4 months (almost every day.)
Been putting them in the incubator for the last 6 weeks in the hope that my Hamburg boy would have fertilized them instead of the 2 Barnevelders that i have in that coop.
We have 7 hens all diferent breed with those 3 roosters. All the other ones have been fertilized and have been hatching like a charm. But the Hamburg girl keeps having clear eggs. So far put in about 20 eggs from her over the last 6 weeks. She does get the 'love' of the boys , seeing her messed up back!
Any thoughts if that can still chance or do I just have to come to grips with that she will be infertile for the rest of her live?!!?

 

[raymondjames]

Just confirm that the hen is mating. When mine mate, you can even see the cloaca contact (?). Maybe she will be infertile, or maybe just for now. Do you know another way to tell fertility?
Crack her egg open
Flip the yolk over until there is a white mark (not to be confused with the chalaze)
Identify the mark: If it is larger, rounder and sometimes donut shaped (yellow in the middle) it is fertile. The mark is called a Blastoderm.
If it is smaller and irregular it is not fertile, called a Blastodisc.

There could be incubator problems

 

[DutchChicky]

Thanks for info

She does get mated as far as I know, her back isn't bare but definitly missing lots of feathers because the roosters go on top. All the other hens in the same coop are all fertile and hatching nicely.
Just checked the yoke and in one was no rooster pick and the other one , might have been a little one, not sure though. Will check it more. Maybe i'll seperate the 2 Hamburgers from the rest to make sure he mates with her. Just didn't want to go that route , afraid I won't be able to re-introduce them to the old flock without fighting