I am converting an old shed / barn into a chicken coop. This thing is 40+ years old but it is pretty big and still sturdy. Probably about 10' x 20'. There will be plenty of space for what will eventually be almost 25 birds in there. I will have 8 nesting boxes and tons of perch space. I have to patch up a few holes here and there but there will be no leaks and no water that will run through it even during a storm. There will also be a pretty big run area all around the outside of the barn. It just has a dirt floor though. Do I have to put in a raised floor and if so, what is the reason?