If you can free range daily for more than a couple hours, that will help a lot - I wasn't sure if that was an option. I assume the roost bar goes completely across width wise so at least there is enough roost space for 2 birds to sleep, which is a plus.
You know, worst case scenario, it should hold up for at least a couple of years. If space really does seem to be an issue (or if you decide you want more birds) you can get a bigger unit down the line and use this for brooding chicks or integrating new birds.