1. American Veterinary Medical Association. 2008. AVMA issues - A Comparison of Cage and Non-Cage Systems for Housing Laying Hens. Accessed Sep. 2017. https://www.avma.org/KB/Resources/Reference/AnimalWelfare/Pages/AVMA-issues-A-Comparison-of-Cage-and-Non-Cage-Systems-for-Housing-Laying-Hens.aspx.
2. American Veterinary Medical Association. 2012. Literature Review on the Welfare Implications of Laying Hen Housing. Accessed Sep. 2017. https://www.avma.org/KB/Resources/Reference/AnimalWelfare/Pages/AVMA-issues-A-Comparison-of-Cage-and-Non-Cage-Systems-for-Housing-Laying-Hens.aspx.
3. The utilization of the Welfare Quality® assessment for determining laying hen condition across three housing systems;Blatchford;J. Dairy Sci.,2016
4. Coalition for Sustainable Egg Supply (CSES). 2015. Final Research Results Report. Accessed Sep. 2017. http://www2.sustainableeggcoalition.org/final-results.
5. California Assembly Bill 1437. 2010. Accessed Sep. 2017. http://leginfo.legislature.ca.gov/faces/billTextClient.xhtml?billid=200920100AB1437.