The time to move them will depend on your weather and your coop.
I just put mine out today and they hatched out 4 weeks ago. It is 90's in the day and upper 70's at night here.
It may be cooler there in Kentucky, but if your coop is escape proof for chicks (they can squeeze through very small openings), you can probably move them as soon as they are completely feathered out at around 7-8 weeks.
You didn't mention the chicks age, but if you think it's too cool at night and you want them out of the house you can always put the heat lamp in there for a few weeks.