Resources:

• Effect on Housing of Trasmission of Salmonella
  
  The results of a new study from researchers in Belgium suggest that any shift from conventional to alternative housing systems for laying hens should be accompanied by a concern for optimizing and maintaining salmonella surveillance programs, due to an increased risk of bird-to-bird transmission and internal egg contamination in some non-traditional housing systems. 

  J. De Vylder, J. Dewulf, S. Van Hoorebeke, F. Pasmans, F. Haesebrouck, R. Ducatelle, and F. Van Immerseel
  Horizontal transmission of Salmonella Enteritidis in groups of experimentally infected laying hens housed in different housing systems
  Poult. Sci. 90: 1391-1396.

  Physical quality and composition of retail shell eggs

• Microbiological Comparison of Eggs from Cages vs. Floor Housed Hens
  Buhr et.al., U.S. Poultry & Egg Association Project No. 641, August 2010
  
  USDA and University of Georgia researchers compared the microbiology of eggs obtained from layer hens housed in conventional cages, wire slats, and floor shavings treatments. Non-washed eggs from the floor treatment had significantly higher aerobic bacteria numbers (APC) than eggs from cage and wire slat treatments. Washing eggs significantly reduced APC levels and resulted in similar APC levels for the three treatments. In addition to higher aerobic bacteria levels, the potential for horizontal transmission of Salmonella and Campylobacter was found to be greater among hens housed on floor shavings.

  PSA Emerging Issues Symposium: Social Sustainability of Egg Production
  Current knowledge and knowledge gaps requiring further research for the interrelated elements of a sustainable egg production system are reviewed in these papers presented at the 2010 Poultry Science Association Annual Meeting

  Introduction - The Socially Sustainable Egg Production project
  J. C. Swanson, J. A. Mench, and P. B. Thompson
  Poult Sci 2011 90: 227-228.
  
  Sustainability of egg production in the United States - The policy and market context
  J. A. Mench, D. A. Sumner, and J. T. Rosen-Molina
  Poult Sci 2011 90: 229-240.
  
  Economic and market issues on the sustainability of egg production in the United States: Analysis of alternative production systems
  D. A. Sumner, H. Gow, D. Hayes, W. Matthews, B. Norwood, J. T. Rosen-Molina, and W. Thurman
  Poult Sci 2011 90: 241-250.
  
  The impact of different housing systems on egg safety and quality
  P. S. Holt, R. H. Davies, J. Dewulf, R. K. Gast, J. K. Huwe, D. R. Jones, D. Waltman, and K. R. Willian
  Poult Sci 2011 90: 251-262.
  
  Environmental impacts and sustainability of egg production systems
  H. Xin, R. S. Gates, A. R. Green, F. M. Mitloehner, P. A. Moore, Jr., and C. M. Wathes
  Poult Sci 2011 90: 263-277.
  
  Hen welfare in different housing systems
  D. C. Lay, Jr., R. M. Fulton, P. Y. Hester, D. M. Karcher, J. B. Kjaer, J. A. Mench, B. A. Mullens, R. C. Newberry, C. J. Nicol, N. P. O’Sullivan, and R. E. Porter
  Poult Sci 2011 90: 278-294.

  Physical quality and composition of retail shell eggs
  Poultry Science 2010 89: 582-587 (March 2010)
  A USDA Agricultural Research Service study examining various aspects of egg quality shows no substantial quality differences between organically and conventionally produced eggs.  

  Putting Meat on the Table: Industrial Farm Animal Production in America
  The Pew Commission on Industrial Farm Animal Production was funded to investigate the problems associated with industrial farm animal production operations and to make recommendations to solve them.
  Executive Summary                  Full Report

  Response to the Final Report of the Pew Commission on Industrial Farm Animal Production
  American Veterinary Medical Association stated that both in substance and in approach the Pew report contains significant flaws.
  Executive Summary                   Full Response

• Laywel Report
  

  LayWel is a European research project that studies the welfare implications of changes in production systems for laying hens.

• Backgrounder: Welfare Implications of Laying Hen Housing
  

  American Veterinary Medical Association’s backgrounder indicates all housing systems have advantages and disadvantages.

• Food Safety and Public Health
  This United Egg Producers factsheet discusses the risk and exposure to Salmonella and Avian Influenza in various housing systems.

in the news:

Links:

• American Egg Board
  www.goodeggproject.org
• United Egg Producers
  www.usaeggfarming.com
• American Humane Association
  www.americanhumane.org
• Center for Food Integrity
  www.foodintegrity.org
• Farmers Feed US
  www.farmersfeedus.org