Natural rearing versus incubator/hand rearing

We've finally integrated ALL of our chickens (except for the three older roosters), into the main coop.  That includes the two chicks that were reared naturally by Miss Connie.

This means they all have access to free ranging, but they almost always stay near the coop and run area.  All of them except for these two;

The two that were naturally raised.  They spent the better part of the day hanging out with the group of us, working on the container.  The others stayed close to coop, or in the coop itself.  These two were duly rewarded for their companionship with some rice and bread crusts. 

They by far seem the most well adjusted.  I don't understand why, they've had very little handling or interaction with us, except for the normal feeding and watering.  It will be very interesting to see how they progress.

It does say something for natural rearing.