I only did the light inside when they first started to go outside as young pullets.  Once they learned it I left it on for another 2-3 weeks.
FYI I just used LED Xmas lights the little tiny ones. The soft off white color. I didn't even unwind them, just left them bunched.
Timer set it for 1 hour before dusk and off 1/2 hr after it was actually dark.
Now I just use the timer to turn the fan on to exhaust the air out of the coop when it is hot during the day.
	
		
			
		
		
	
				
			FYI I just used LED Xmas lights the little tiny ones. The soft off white color. I didn't even unwind them, just left them bunched.
Timer set it for 1 hour before dusk and off 1/2 hr after it was actually dark.
Now I just use the timer to turn the fan on to exhaust the air out of the coop when it is hot during the day.
 
	 
 
		 
 
		 
			
		
		
		
	
	
			
		 
 
		 
			
		
		
		
	
	
			
		 
 
		
 
 
		
 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		