Instructions
Download Brick Pack mod. You can find a link in the Resources section.
Open the pack using unzipping software, such as "Win7" or "WinRar." If you don't already have unzipping software, you can download and install either of these programs for free.
Drag and drop the file "Z - D - Brick Wall Pack.z2f" into the game's update folder. By default, it's located at "\Program Files\Microsoft Games\Zoo Tycoon 2\Updates."
Start the game.
Click on the Build icon and then choose the Wall icon. Click the screen and drag your mouse to construct the brick wall.