If you had six eggs or fewer to hatch, would you incubate them or put them under a broody if you had both options? Trying to decide which will give the eggs a better chance. They are on day 17.
I'd keep them in an incubator. In an incubator, you can keep the humidity and temperature at the proper levels. With a hen, you would run the risk of her leaving the eggs, attacking the chicks when they hatch, or destroying the eggs. This isn't to say that a mother hen isn't a good mother, but an incubator allows you to control more variables.
Momma hens don't worry if a chick is not hatching fast enough and decide to "help" the chick hatch. so, 6 in one hand, 1/2 dozen in the other.