I have 2 1 &1/2 year old black sex link hens that have never layed an egg ever! These 2 birds were loners and always shunned by the other hens. On the other hand, they were our roosters favorite mounts. They undoubtedly had the best markings of all our birds and were our favorites. The best looking birds on the block so to speak. Black sex links are known for superior egg production and it baffles me as to why they didn't lay a single egg. I have read that some birds never produce but have never found out the reason why? Any feedback would be appreciated.