My breed sorta started off in a farm way out in the boonies, a lady told me some 20 yrs ago she got a BBRed and Black Rosecombs, together with some heavy laying chickens that by her discription I think were Black stars. She hasn't added new blood to that line ever since and I caught 1 single hen from her birds(the rest are too wild) in the spring 6 yrs ago(still got her, took me 2 yrs to get her sorta tame). That woman had like 50 wild, black, medium sized birds running around her property. Birds that have never been held or had any sort of contact with people or an enclosure.
Took us forever to catch that one hen.
So with that one hen and a LeghornXBarred Rock rooster I started off my breed quite by accident about 6 yrs ago, but didn't acctually try to make a breed until 4 yrs ago(when I had all these neat youngsters).
The original hen herself isn't much of a broody, and the previous owner said her chickens usually have no more then 20 chicks each year all together. Since only 1 or 2 of the hens would go broody.
So I am not 100% sure where the broody comes from, none of the breeds in these birds are really the broody types.