I have a hen who turned two at the end of last September. She is half white leghorn and half something else-- probably Buff Orpington or Brahma. She has laid really well, but about 4 days ago she laid a tiny white yolkless egg and hasn't laid any eggs since. She seems healthy and happy. Someone suggested that she may be done laying forever. Is this typical of this breed mix? I have a Barred Rock girl who will be 4 this month, and she is still laying great.