Can chickens handle doggie doors?

I'm chicken-less now, but I've been thinking about getting a couple hens.  Can I put a doggie door on a coop?  Or maybe no door at all?  I'm a family man and homeowner, so I've already got plenty of things to do around the house.  I think I can handle all the other jobs of keeping chickens, but the thought of having to close their coop door every night and open it every morning is a deal-killer for me.

I'll have an enclosed chicken run with raccoon defenses all around.  Would they be OK to go in and out as they please?  I live in the Los Angeles suburbs, so it's not like they need a door to protect them against blizzards.