[Real Rush]

Just that... what makes a blue hen mare? Are there "requirements"? Do their immediate offspring need to have reached a certain level of success, or must it be passed down through several generations in order to qualify?

For example: with the smashing debut by Ebloussaint (Zenyatta's li'l sis), as well as a couple other winning fillies, would their dam Vertigineux be considered a blue hen? Or would one of the mares need to also produce winning foals in order for Vertigineux be considered? Thanks to anyone who can satisfy my curiosity!

[Flypony]

Blue hen mares, produce high quality foals, that will go onto producing high quality themselves. Vertigineux will be dependant on what her foals produce, to attain stature as a blue hen mare.

[LaurieB]

What Flypony said.

Plus, while Eblouissante ran a great debut race, that by itself isn't enough to elevate her dam to top producer status (of course in this case Zenyatta and Balance have already done that). A maiden win, however nice, is simply the first step in what will hopefully go on to be a stellar career.

[gumtree]

A “Blue Hen” is mare the foundation, “patriarch” of a prolific producing family. Always on the “dam side” bottom line of a multiple generation pedigree page This being through her daughters, granddaughter, etc. Generally producing multiple stakes horses of the highest caliber. Who then go on to do the same. Or dams of the same family that are unraced or lightly raced but produce stakes winners also.
They are far and few.

[nasalberry]

A “Blue Hen” is mare the foundation, “patriarch” of a prolific producing family. Always on the “dam side” bottom line of a multiple generation pedigree page This being through her daughters, granddaughter, etc. Generally producing multiple stakes horses of the highest caliber. Who then go on to do the same. Or dams of the same family that are unraced or lightly raced but produce stakes winners also.
They are far and few.

Confused here. Don't you mean "matriarch?"

[Laurierace]

Yeah, no matter how nice she is no mare is ever going to be a patriarch!

[gumtree]

Confused here. Don't you mean "matriarch?"

You know, I debated between the two. Yes, matriarch is more gender specific. But I thought the definition of patriarch; biblical ancestor, head of the family, respected senior, etc was more fitting. Gender aside. And considering in the animal world the female of most species is the “bread winner” and leaders. Besides don’t we live in a gender neutral society these days? Especially when it comes to working with horses.

[nasalberry]

That may be: However, there are still specific terms used e.g. "tail-female" and even "Blue Hen" that refer to only one sex.

[Lynnwood]

When I think of Blue Hen mares I think of mares like Grecian Banner , La Troienne , Lady Josephine ,

[nasalberry]

... Mumtaz Begum, Personal Ensign ...

[Lynnwood]

... Mumtaz Begum, Personal Ensign ...

100% both mares with direct maternal ties to the aforementioned above. Gercian Banner being Personal Ensign's dam and Mumtaz Begum , Lady Josephines granddaughter.

Really great strong marelines.