My Christmas project was to create a new house for our chickens that was easier to clean than the last one - which was realy just an oversized dog kennel - which you can see behind sticking out from behind the new version in this phone photo:

I used some plans from buildeazy.com which made things a lot simpler, but I did make a few changes. The coop has a window at the rear which I got from a local demolition yard for $65. There's a lot of timber in this design, probably more than the chickens appreciate, but at least it will never blow away in the strong winds we get.
All up, I think it cost about $NZ1000. A local business sells ready made units for about $NZ800-$NZ900 but they are quite a bit smaller and nowhere as sturdy as this one.