not mating

I bought a proven rooster 3 weeks ago but all of my recent eggs are unfertilised. I know he has fathered chicks before but since arriving he has not mounted any of my 4 ladies. I attached a picture of an egg, it doesnt have the bulls eye so its definitely not fertile right? Any help appreciated x

Hi A couple of weeks ago we bought a pair of buff orpingtons. The 10 month old rooster was proven since he had been kept in isolation with his hen who had then gone on to hatch chicks. When they first arrived I cracked an egg from the female orpington and saw it had a white spot indicating it...