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Evaluation of Free-Range Housing

07/29/2018

The Council for Agricultural Science and Technology (CAST) recently released issue paper IP 61 co-authored by Dr. Jacqueline Jacob and Dr. Anthony Pescatore.

 

The important conclusions from the review are that the advantages of free-range production relate to consumer perception rather than any benefit to the flocks. The principal take-away messages are:

  • Greater space does not necessarily enhance welfare.  Flocks on free range systems have higher mortality than when confined to barns.  Predator loss, exposure to pathogens and parasites, inclement weather all detract from “welfare”.
     
  • Outside access does not enhance nutritional value.  There is no nutrient that can be obtained from pasture that cannot be incorporated in eggs from flocks fed a balanced or supplemented diet.
     
  • Food safety is inferior on pasture compared to confined systems.  It is impossible to decontaminate pasture infected with Salmonella.  Although there is no appreciable difference between clean eggs laid on pasture and those from cages or barns, eggs with heavy fecal contamination from either system will have a higher probability of internal contamination as a result of shell penetration by motile bacteria.
     
  • Flocks on pasture are susceptible to ingestion of toxic compounds which may be deposited in the egg.  Backyard chickens in urban areas have lead levels which in some cases exceed accepted tolerance values.
     
  • Flocks with outside access are susceptible to infections carried by free living birds.  These include avian influenza, Newcastle disease, colibacillosis, pasteurellosis and erysipelas. The last two infections are re-emerging as important conditions which almost disappeared in egg-producing flocks after confinement systems were introduced.
     
  • Pasture management is non-sustainable, requiring extensive land which could be used for crop production or other livestock, and requires more energy and labor for the same quantity of eggs produced in barns.
     
    The differential in cost between eggs derived from flocks held on pasture and those in barns cannot be justified by any quantifiable improvement in either welfare or product quality.  An affluent minority of consumers is apparently willing to pay a $3 to $4 differential for what they perceive as advantages. This market is limited as evidenced by the small proportion of flocks reared on pasture and a virtual plateau in expansion in this segment of egg production.