I've been using nothing but cardboard boxes for brooders for the past three years. I cut 6 mil plastic sheeting to fit the bottom and spread the wood shavings over that, two inches deep. (Nix on the foil, they would shred it and ingest it.) The cardboard never suffers from any dampness that may occur. I even put two boxes together this year with a pass-through cut into them so the tykes had a two-room condo. I also place the boxes on tables so I approach the chicks from the side, thereby avoiding the fear that is generated by coming at them from above. I cut access doors into the sides, lightly scored at the bottem edge to serve as a "hinge". I secure the doors with popsicle stick latches held in place with a nut and machine screw.
To solve the water bottle problem, and to keep it from getting fouled with the wood shavings, I put the bottle in some orange sack netting, the kind those tiny mandarins come in, secure it tightly around the neck, invert it, place an "s" hook on top, and hang it from a stick I slip through two slots cut into sides of the cardboard walls near the top. It keeps the water fresh as the moment you put it in, and no matter how active the babies get, they never get any shavings in it. The little ones favored sleeping underneath their water bottle for some reason, another bonus.
I place cheese cloth over the top so when they start trying out their wings in a few weeks they can't get out.
