I have been using a 250 watt red bulb the past 2.5 weeks and all has been well. Raising it so as to reduce the brooder temp. I thought about putting in lower watt white bulb to getting them use to cooler temps. I went in while they were sleepy and switched out the bulbs. Within 30 seconds they were up and looking at each other like a veil was lifted and they had never seen each other before! There were easily 5 kung-fu sparring events going on at any one time! Big ones and little, boys and girls! Flying about and crazy! I pulled the plug and they stopped, changed back to the red bulb, flipped it on and they went back to quietly peeping and returning to roost and snuggling. They way they walked back to the roost reminded me of the Eloi in "The Time Machine" when the sirens sounded and they zombie walked right into the Morlock's trap!! Good movie BTW! Does the white vs. the red light make that much of a difference in their behavior and when IS a good time to change lights of so?!