The high stocking density, stress, unhygienic conditions, lack of sunlight, and breeding practices typical of industrial poultry and egg production systems may facilitate the emergence and spread of diseases, including highly pathogenic avian influenza viruses with public health implications such as H5N1.
"Human Health Implications of Intensive Poultry Production and Avian Influenza,"
Agribusiness Reports: Vol. 2011, Article 4.
Available at: https://www.wellbeingintlstudiesrepository.org/agreports/vol2011/iss2011/4