WHY? The hardest part is the actual killing. I can understand you worrying about doing it because I did at first. It was the thought of not doing it cleanly and causing the bird to suffer. I use a " humane, wall hung poultry dispatcher" I found on ebay. If you have it at a comfortable height...
If you like keeping track of everything, get yourself The Poultry Keeper's Almanac (PKA). It will do everything from helping keep track of incubating eggs to recording what lives where, calculating/ tracking feed costs to printing your own egg box labels. It's inexpensive, easy to use and comes...