I have not had my GSBR's (via XW Poultry Ranch) go broody yet...then again they are only about 16 months old. Have one doing her first molt..hopefully the others will follow suit before November when I plan to show a few! They have been decent layers for non-hatchery birds too.
Time will tell on the 'brood' factor.
I have 5 GSBR from Matt from Jwhips stock I have had 2 of the 5 make an attempt at going broody on me they are determined and hard to break so yours will try in due time, this I'm sure, I have 9 of the F1 Delaware project girls Mrs.Kathy had made by crossing GNH x GSBRs they are a very broody bunch I have at least one a month in the broody buster pen sometimes 2-3 at a time so the BRs most definitely have this one requirement for sure to go down in their stats on being a Heritage type breed for sure.
Jeff