Hatch Time-- Under Hen v. Incubator?

Do eggs hatching under a broody hen, instead of in an incubator, hatch at a more predictable time, generally? I put my fertilized eggs under my broody hen in the early afternoon of September 6.

Do you think they are more likely to hatch this afternoon, during the night, or tomorrow? I have read conflicting reports, and I'm thinking some of the reports may have been based on eggs hatching in incubators rather than eggs hatching under hens.

Thanks for your help,

Clare, who wants to go leaf-peeping today but wonders whether she might miss out on the hatching excitement if she leaves.