We have a Polish that is a little over a year old. She layed just as we expected for many months. It has now been 3-4 months without an egg from her. She definitely moulted but now looks back to normal and has for a while. She acts perfectly healthy. We have a Buff Orp that is the same age that lays almost everyday. Same food, same yard, same coop. Is it possible that she's barren?