The 1" holes near the top are both screen. The entrance is a 1/2" hole near the bottom. Robbing is a big issue here and the top vent holes help tremendously. They lure the robbers away from the entrance.
They are made out of 3/4" plywood. They actually hold up pretty well when painted as they are in storage during the worst weather (spring, fall, & winter)
Here are some details, complete details are in the attached PDF.