You can easily make a channel out of 1x3 or 1x4 lumber with a door that slides in the track. I use a piece of 3/4 inch plywood cut 1/2 inch narrower than my channel is. It allows the plywood to slide up and with a rope be hooked in the up position.
I use a simple piece of 1x3 in similar channel on the door and frame to lock it each night. It is kind of medieval looking lol. Think big castle door in the movies.
Below is another option. This door (on the right lol) is hinged and has hooks to hold it open and closed. Simple but worked well.
This one had a side sliding door that ran in a track made the same way as the ones that slide up. However it did not have a lock. It also had issues with the track in the winter filling with ice and snow. BUT it may give you the idea of how to do one simply that raises vertically.
The easiest thing I can come up with is a shutter style design. It will be what is on the window of this coophttp://www.backyardchickens.com/a/the-palace This should be good enough. If u can mount it on the outside so predators cant push their way in.
Hope this helped!
Edited by blucoondawg - 10/9/15 at 6:31pm