1. AVMA. 2012. Literature review on the welfare implications of laying hen housing. Accessed May 2017. https://www.avma.org/KB/Resources/LiteratureReviews/Documents/laying_hen_housing_bgnd.pdf.
2. Brambell F., and Technical Committee to Enquire into the Welfare of Animals kept under Intensive Livestock Husbandry Systems., 1965. Report of the technical committee to enquire into the welfare of animals kept under intensive livestock husbandry systems London: Her Majesty’s Stationery Office.
3. The use of cottonseed meal with or without added soaptock in laying hen diets;Davis;J. Appl. Poult. Res.,2002
4. Egg production and welfare of laying hens kept in different housing systems (conventional, enriched cage, and free range);Dikmen;Poult. Sci.,2016
5. The pros and cons of cages;Duncan;World’s Poult. Sci. J,2001