If you are talking about other little chicks, i would go with the abive advice. You can put chicks on with the mother and babies at night as well when everyone is calm.
If you are talking about adding non laying, feathered chickens, my advice would be to wait or have a good isolation zone ready. Bringing in other chickens who are not babies means you are bringing in unknown flora, fauna and bacteria. Your chicks and your hens will have no immunities built up to what they bring in and your hen that was jjst broody is not going to be at her most robust. The stress of adding chicks and pullets at the same time could be enough to confuse your flock into a semi peaceful merge, or it could mean a lot of fighting, stress, bad eggs, and blood.
If i put myself in your shoes and i had to have adult hens, hatched chicks, and pullets at the same time, at my particular home i would build another coop and put the pullets in the front yard, near our fence. Our flock is in the backyard. After a month i would open up the run for the pullets so it extended to the fence line so all of the chickens can see each other and interact, but cannot hurt each other and the chicks would at that time be too big to get through the fence. And i would wait unti, the chickens are spending time together relaxing through the fence. We've done this before, minus the chicks. It took around a month of fence-interaction until we could see the chickens wanted to be together. We brought their mobile coop into the backyard and there has never been a single fight.