How to introduce a new mama hen and chicks to an existing flock

[mamahen amateur]

I just purchased a mama hen (5yo silkie/Orpington cross) and her 12 adopted chicks (6 days old). I have an existing flock of 10 pullets (4 wynadottes, 4 leghorn/light Sussex and 2 orpingtons), ages ranging between 9-17 weeks old) all free ranging. I've put the mama and chicks in a separate shed the first day - but they are used to free ranging from birth and are quite hardy.

How should I introduce them to the existing flock so they can free range again? I don't have the luxury of a seperate wire area. Do I just let them out a few hours a day and watch them closely or are the other pullets likely to peck them to death?

 

[Lin20]

The other pullets are likely to peck. You have to watch over them and protect them if need be.