Everynight probably about 30-45 minutes before it gets really dark I head out and round up my five chickens and 1 duck. 4 of my chickens sleep in an outside coop, that is a rubbermaid outdoor storage container, that is reinforced with a padlock, some other device to hold the doors together, and a rock! In the summer they are getting a new one made out of an old storage cabin. And our duck sleeps in a homemade coop thing, that my dad made, but has definietly seen better days, and my 1st chicken (she is special) sleeps in the garage.
I personally like putting them to bed, because I can say goodnight, and I don't have to worry about them. The raccoons where I live are HUGE, mean, and aggresive. They got our first duck who was in our garage when she was still little, it was awful. They have tried really hard to get it, sticking their fingers through the air holes, climbing on top, and circling the entire coop. And if I know I won't be home in time to put them away either I put them away before I go, which they don't like, but hey it keeps them safe, or I make sure a family member can lock them up. I have never tried letting them put themselves to bed before, I just couldn't take it if something happened to one of them.