Super cute! Have they moved out to it yet? Definitely expand when you get a chance. The general rule is 4 sq ft per full size bird in the coop and 10 sq ft outside. With 5, you should target 4'x5' or any other combo for 20 sq ft of inside space. The other issue I personally ran into is roost space. The rule of thumb is 1 linear foot per full size bird. I cheated by having two roosts, but you need around 10-12" between each roost to keep them from pooping on each other.
I think you could add another pair of legs to your hutch to make it work fine, at minimal cost. I think you could add a poop board, with no issue as well. That has been a chore saver for us, for sure. I really like the look of the hutch, so I would definitely try to build on to it.
