Stronger? No.
Though broody hens are definitely better hatchers than any man made incubator.
I purchased 15 Serama eggs from a breeder in Florida, and placed 8 (the more damaged ones) and 7 in my incubator. By day 5, 5 of the eggs had quit. This may be because of my incubator location, but not the point. All of Sunny's eggs were doing fantastic, even one I moved from my bator to her because it seemed to have weak veins.
On day 21, Sunny hatched 6 chicks. I hatched 1. My bad hatch may have been because of my incubator location, but even with shipped, damaged eggs, Sunny got more than a 50% hatch rate. Pretty impressive if you ask me.