Modern chikens, I mean human creations, mature in less than two monts of age, these animals grow so fast that can not even stand on their feet if they do not get slaughtered, they grow too fast for their bones to support the weight. Also the industry, here in Europe and I assume in USA also does not grow male chicks and they kill them right after birth, maybe you could find someone local and ask for those to grow yourself? just a thought.