I have two silkie hens who have been good layers until the past two weeks one stopped laying and the other is just putting out the tiniest eggs. They are only 3 yrs. old and were laying fine a few weeks ago..have also been noticing egg yolk stains inthe nest box so I don't know if she's breaking them ,eating them or just passing the yolk?? What's up with that? Previous eggs were about the size of a store med.and very tough shell, now it's about the size of a dove egg!?