Is there any way to tell how old a hen is? My hens have one by one stopped laying, and nothing else fits. I am wondering if maybe the farmer who sold them to me lied about their age. I was a greenie and knew nothing. He said they were 20 weeks old, but...they could have been ancient, and how would I know?! And...they have never moulted. It's about 14 months since I got them; shouldn't they have moulted by now? Unless they've long since passed their prime?