Please understand that hens are not natural mamas. Even a broody hen won't be inclined to mother chicks unless she has them hatch under her after sitting on them for three weeks.
Your broody is preoccupied with her fixation on needing to sit on eggs. As she returns to normal, she is capable of anything, including hurting the chicks. It's not a good idea to put her with the chicks. Only on very rare occasions has it been successful to have a broody adopt already hatched chicks.
It's safer for your chicks to keep them in the brooder with an artificial heat source. I recommend the Mama-heating pad chick cave system. If your chicks are just a few days old, they would be very likely to take to this system. It's very natural and there's no danger of overheating from a heat lamp.
