I've been lurking on this thread for awhile and trying to learn as much as I can
I raise Barnevelders which I believe are a heritage breed since they are listed by the HPBAA and meet the requirements for being heritage. I've been working on bringing back the dual purpose qualities and improving egg quality for a few years. I do have two project lines that involved outcrossing Barnevelders to wyandottes and Dark cornish. I don't know how the project lines would fit into the Heritage requirements though they are high% Barnevelder blood at this point.
Here's one of my blue pullets from this year.

I've found them to be a very hardy breed in my area though the excessive heat sometimes bothers them when it gets above 100 for days on end. The hens will hatch out eggs and are excellent mothers.

I tend to spoil my chickens with good feed, but I gave 12 pullets to a neighbor in March and she hasn't even gone through 2 bags of feed. She free ranges them and feeds them table scraps. They have been providing her with plenty of eggs despite having to forage for most of their diet.
Trisha

Here's one of my blue pullets from this year.
I've found them to be a very hardy breed in my area though the excessive heat sometimes bothers them when it gets above 100 for days on end. The hens will hatch out eggs and are excellent mothers.
I tend to spoil my chickens with good feed, but I gave 12 pullets to a neighbor in March and she hasn't even gone through 2 bags of feed. She free ranges them and feeds them table scraps. They have been providing her with plenty of eggs despite having to forage for most of their diet.
Trisha