Some evidence in Australia and New Zealand has indicated that music may help to keep chickens calm and happy, thus helping them to grow larger, faster. The relationship to egg laying rate has not been seen on a large scale (that we are aware of). You might be interested to read this article about music as related to growth in chickens in Taiwan.
Belgian Bearded D'Uccle hen
This is also an oft-used science project for kids, too. If you decide to try a science project, please let us know your results!