Silkies not laying

Hi back in february we bought a lovely pair of white silkies but we have never had an egg from her, we were told  by the breeder that he had fed them on wheat and pig grower to get the big size, we got them onto layers pellets, they are out on grass and are very friendly healthy birds, I wondered if anyone knows if their early diet could have permanently affected the hen, they are 8 months old

Thanks, hopefuly she will start to lay soon then