Until a few days ago, I used a small lamp with a white bulb for my silkies as their heat lamp. The white female sure was grouchy. I just took the red lamp off of the big girls (since they're fully feathered) and put it on the silkies. Now the Silkies both run up to me, will let me pet them and even will roost/snooze on my arm. This is proof in my book that white light makes them more agitated - as mentioned on multiple websites.