Would you be able to keep the ducks apart from her until they get older? I would be afraid that the chicken is the queen of the coop right now and any new comers, she's liable to attempt the pecking order and hurt them.
If you get a drake, chances are the ducks will not bother the chicken at all and just hang with there own kind, but be scared of the chicken for some time.. you may still have the pecking probably until she gets used to them...
I have my bantams with my ducks and when the ducks had babies, the bantam would toss the babies up in the air trying to kill them, I had to keep the youngsters separate until the ducks could hold there own ground.. Once the babies got older and bigger, the issues went away. No more attacks.
That's the only concern I can see is your bantam being the queen and no one is welcomed. Or she could be thrilled to have the company..
Is your bantam sweet? If they have a nice friendly calm attitude then you may be ok. But if you can't go up to her and touch her because they act like your gonna kill them then I would be on a watch...
Are we talking just one chicken with the two ducks??
