Complex sentence: Advocates of factory farming claim that factory farming has led to the betterment of housing, nutrition, and disease control over the last twenty years, while opponents claim that it harms the environment, creates health risks, and abuses animals.
Split into simpler sentences: Advocates of factory farming claim that factory farming has led to the betterment of housing, nutrition, and disease control over the last twenty years. Proponents of industrial agriculture argue for the benefits of increased efficiencies, while opponents claim that it harms the environment, creates health risks, and abuses animals.