Mesmama- That's my understanding. The idea being that when they are subjected to cooler air, their little bodies tend to naturally feather out more quickly as a way of protection from the cold. When they are subjected to constant heat and light, their body temps effectively being regulated for them instead of learning how to regulate for themselves, they tend to not develop feathers as quickly. I have several that are 2 weeks old today and already have wing, tail and shoulder feathers. A couple even are getting some chest feathers developing. Their down is definitely spread much more thinly and it is just so exciting to see them change so much!
If I am being honest, I love the "awkward teenager" stage in chick development more than the fluffy new chick stage. They are just so cute when they are still scrawny and feathering out!!!
I can't wait to see all the changes! When my broodies hatched a couple chicks last year it was different because the hens aren't very tame so they kept us at a distance. So this will be fun!