A beard on a turkey is a secondary sex characteristic, just like a man growing a beard. So if you see a hen (or a woman) with a beard they have a hormone imbalance. An example would be when female athletes take steroids, they start growing beards because all that testosterone they are adding to their system.

I think the real question is this: do gobblers have the "beauty is only a light switch away" philosophy and only breed bearded hens at night? haha