If you think on it and decide you want to mix them, I will let you know when we have more extras! Our Svart Hona hen actually went broody a few weeks after she started laying! ... once she started laying again we always take her eggs but she is sneaky and still tries to lay on them if we don't get them in time.
It's so funny because the only other hen we have had that went broody was our silkie hen years ago. Out of the 7 breeds we have owned, we've only had a broody silkie and a broody swedish black hen. I'm not sure if that's the norm, but it was with ours!
After thinking on it, I do want to do this! Since I have Silkies for their reputation of broodiness, I will go with the Swedish Blacks, as your foundation hen has gone broody (more than once?). If you tire of fighting her and have non-broody daughters of hers, I'd be very happy to have her as well. This will be a big boost in my efforts to breed my Silkies larger ... I know what I end up with won't be actual Silkies, so I've started referring to them as "Silkiebators". I have a buyer of my extra cockerels, and cannot lose or dilute the Fm gene or I lose my customer. So, these Swedish Blacks will be a perfect fit for me.