Adding a bottom floor to a rabbit hutch?

[koakritters]

I've got an old rabbit hutch that's one of those standing ones, about 2 1/2 ft off the ground or so. I want to add a bottom floor to it so the chicks have 2 stories to roam around. I was planning on putting 2x4s around the bottom and attaching chicken wire to the sides to make an enclosed area, but was wondering if anyone's ever done something like this? I can't figure out how i would cut a hole in the bottom of it (it's chicken wire type bottom that they are on right now) and then adding a ramp down without damaging the rest of the floor... any ideas? does this make any sense?

 

[allieloveschickens]

Could you put a wood top floor in instead of wire so that it would be sturdy enough to cut a hole in? Or you could but some little cross beams in around the opening to nail the wire down to so that it wouldn't sag or fall apart.