If you offered her the oyster shell on the side, it wouldn't matter. She would consume that too meet her extra calcium needs if she started to lay again.
Keeping birds on a higher protein level all flock type feed is superior to using layer feed which has less protein and forces them to consume...
It has protein. It also has calcium but not at a level required by an active layer for shell formation.
Feeding chick starter or grower is excellent for hatch to death feeding. As is any All Flock or Flock Raiser type feed. Just put one or two containers of oyster shell out for free choice...