infertile rooster?

[blondelabchick]

Twice I've tried to hatch eggs in the incubator and no luck, and my 1 hen sat on her eggs for a month and then threw them all out and broke them. could my rooster be infertile? I've hatched other eggs, not by these chickens in the incubator and never had a problem. My rooster is constantly after the hens, the poor girls have no feathers on their backs because of him.

 

[NancyP]

I am just guessing but maybe a trim around the vent might help him get the job done.
Nancy