This is such a good thread. I get a little bit of anxiety about letting my chickens out when it's cold and rainy, so it makes me feel much better to know it's Ok for them even if it's wet and cold. I don't let them free range while I'm at work. As soon as I come home at 5:00 though, I let them out right away. I feel bad for them because it's almost dark on the weeknights here in Ohio, right now with winter approaching.
They do love to be outside! During the summer they're out every day until dark, then all day on the weekends. I'll have to have my step son let them out on weekdays after school, so they have more time to free range.
A fellow at the Ohio National told me that his birds are much healthier since he doesn't baby them anymore. Good advice!