Article about stress in birds and what can cause it. Even a seemingly small change, can be very stressful for a bird. Because birds are masters at pretending they are OK, until they can't pretend any longer...this atricle is a valuable read.
While this article is geared toward parrots, it does transfer to Pigeons and Doves...it really is about all birds and how we can better understand them.

http://www.vetpets.net/animaltimes/stressinbirds.html

I just found this. Good article. Thanks for posting it. It mentions a lot of things that people may not even think of. Like the light factor, or when they have it dark for sleep. This I have to admit that I am not good about. I spend a lot of time with them, and have so much to do when I get home, that I often keep them up later than they should be. I'm going to watch that, and make a time for lights out, and stick with it. I'll just have to plan my time better. Thanks for the reminder.