They’re D’Uccle’s. How many are you getting? I just don’t personally think it’s a great idea at the moment while your large rooster is being rough with your large hens. But I will tag @aart as they’re far more knowledgable than me and may be able to help you more or tag someone else that does.
I think when there’s an existing problem with large hens being overbred by the rooster, it’s best to think about the safety of smaller chickens who can easily be crushed.
What breed? Mille Fleur is a colour.
Regardless, I think bantams will be too small and are likely to be overbred too. Personally I’d add another 3+ large fowl hens.