My RIR/Araucana hen (24 weeks old) usually lays nice brown eggs. For 2 days now, the eggs look like they have stretch marks on them and are spotted. Is that a sign of the shells being too thin? Our chickens get a grower/developer feed (17% protein) because only half are laying right now (all about the same age). Do they need a change in their feed or add oyster shell? Or is it too much calcium/protein? Today's egg... For comparison...here's what her eggs normally look like... Thanks!