I've compiled a step-by-step guide to making a cabbage tether ball, that the chickens gleefully volley back and forth in the run, catching small mouthfuls with each peck.
Step 1: Get a medium head of cabbage (green or purple*), and slice it in half.
*purple cabbage, used with varying success to dye Easter eggs, imparts a blue pigment to various types of matter.
Step 2: Use a chopstick or other pointed object to pierce a hole in the cabbage. Alternately, Mr. Baker likes to drill though a whole cabbage using a long drill bit.
Step 3: You'll want to feed a string through the cabbage in order to tie it up. Shove a straw through the hole and create a passage through which you'll feed the string.
Remove the straw while keeping the string fed through, and tie the string around the cabbage, knotting the ends together.
Step 4: Tie the cabbage up to the top of the chicken run, and get ready for hours of chicken amusement.
Several hours later you'll find nothing more than a cabbage nub. Coming soon, Mr. Baker has video footage of the buffoonery. Stay tuned.