Something they are eating or drinking in likely the culprit.... Does she eat them herself>?
Feeds high in Omega 3 are also said to cause a unpleasant or fishy tast to some folks. Some folks have very sensitive taste buds and will notice much more than average folks when it comes to egg flavor, same type folks get food and wine tasting jobs
Another thing could be flax seed as in large amounts will add flavor to eggs that is unpleasant to some folks.
My grandpa always said to be careful what to feed the hens cause it would change the egg flavor....
Feeds high in Omega 3 are also said to cause a unpleasant or fishy tast to some folks. Some folks have very sensitive taste buds and will notice much more than average folks when it comes to egg flavor, same type folks get food and wine tasting jobs

Another thing could be flax seed as in large amounts will add flavor to eggs that is unpleasant to some folks.
My grandpa always said to be careful what to feed the hens cause it would change the egg flavor....