If you want the hens to do the work, you have to have a hen who is ALREADY broody, meaning she's already trying to hatch eggs by sitting on the nest ALL the time, only getting off briefly to eat and drink, and pecking to protect them. If you want specific breeds, you have to separate them, cause a rooster will jump on any hen he can catch. The hens can hold semen for a couple weeks, too, so they have to be segregated that long.
Chickens do a better job of hatching eggs than any incubator, but you need a good broody!