You know, that would work well for a coop if attached directly to a run, leaving the front open, and perhaps putting a bit of roof over the part of the run closest to the coop. You can actually house them this way even in most colder climates. Here is a thread that shows what I'm thinking of...
What a great find! I believe I'd turn it sideways, if it were mine, to give them lots more floor space. I'd remove or cut holes in some of the interior boards so they would have access. I'd use one of the spaces as the nest box. It looks to me like you could do the same to create a roost...