Conventional Cages, Cage-Free, Free-Range What Does it all Mean?

Conventional Cages, Cage-Free, Free-Range What Does it all Mean?
May is National Egg Month

May is National Egg Month

I’m a Baby Boomer.  I grew up when life was simpler.  Now things seem more complicated—take eggs for example.  Do I want my eggs to be organic?  Caged?  Cage-free? Free Roaming?  I don’t know—what’s the difference?  What does it all mean?

Our friends at Best Food Facts enlisted the help of experts, Dr. Darrin Karcher, professor at Michigan State University and Dr. Patricia Hester, professor of Animal Sciences at Purdue University to help explain the different systems used for laying hens and the advantages and disadvantages of each.

Conventional Cages

This system provides 67-86 square inches per bird, as well as continuous feed and water. Dr. Karcher explains that the industry currently uses the conventional cage system most frequently.


  • Hens have fewer incidences of cannibalism because of smaller group sizes.
  • Cages provide protection from predators and wildlife.
  • Hens housed in cage housing systems are at a lower risk of infectious disease.
  • Conventional caging does not incorporate the use of litter.  Litter-based systems have been shown to have increased levels of ammonia, dust and bacteria.
  • Hens in cages have improved livability


  • Restriction of natural behaviors: Hens in cages are less able to perform behaviors such as dust bathing.  (Dust baths are a chicken's way of keeping clean. The fine sand or dirt in their bathing area keeps their feathers in pristine condition and helps them stay free of mites, lice and other parasites.) and foraging (searching for wild food resources).
  • Nesting (preparing for laying eggs) and roosting (perching to rest at night) are not options in the conventional cages.
  • Hens may experience overgrown claws.
  • Caged hens have poorer skeletal health because of lack of exercise.

Enriched Colony Housing Units

This system provides around 116 to 144 square inches per bird again with constant feed and water. But there are perches, a forage mat or scratch pad area, as well as a nest box or an area where the birds can have some privacy to lay eggs. Abrasive strips are provided to keep claws trimmed.


  • Hens are better able to express their natural behaviors such as nesting, foraging, and perching than in conventional cages
  • Perches: Hens are motivated to perch, especially to roost at night. Perches improve bone strength


  • Foraging behavior and dust bathing are not expressed as easily as in cage-free systems.
  • Nest-dwelling parasites can be a problem.

Cage Free

There is a colony nest box which usually runs down the center of the house with a slatted area where the feed and water are located so the hens then can go into this nesting area to lay their eggs. Aviaries also fall into the category of cage-free housing where hens can use vertical space to access one or more tiers consisting of wire or perforated floors or platforms.  A littered area for scratching is available in cage-free systems.


  • Barn – and – aviary raised hens show improvement in bone strength, but more bone breakage occurs because of increased activity over hens raised in cages.
  • Increased ability to forage and dust bathe.


  • Birds raised on the floor are more likely to encounter disease carriers in feces or dampened litter, potentially leading to reduced health.
  • Cannibalism and pecking are greater in cage-free systems.
  • Litter – based systems have been shown to have increased levels of ammonia, dust, and bacteria.


The key feature of free-range housing is access to an outdoor area during the day.


  • Hens with access to both indoor and outdoor areas have the greatest range of behavioral opportunities. Hens that spend more time outside have better feather condition.


  • Outdoor conditions could potentially expose hens to toxins, wild birds and their diseases, predators, and climatic extremes. Hens are often reluctant to use the range area or venture far from the hen house resulting in wear of the pasture in the area near the house.

The different systems for laying hens does influence the cost per dozen.  Free-range eggs are about 50% higher in cost than conventional eggs.


Organic eggs come from hens given feed which is certified organic.  There are fewer certified organic feeds than standard feeds and this could be a contributing factor to why organic eggs are more expensive.

Omega 3 Eggs

Omega-3 eggs are a good source of alpha linolenic acid (ALA). Since ALA is an essential fatty acid – it must be obtained from food because the body can't produce it – there is a daily requirement for it. Adult women need 1,100 mg a day and men require 1,600 mg. One omega-3 egg supplies 20 to 30 per cent of a day's worth of ALA.

Is the Nutritional Profile of an Egg Influenced by the Housing Conditions?

That’s a good question.  Free-range hens may forage for bugs and plants, which could conceivably alter the nutritional intake of the hen and hence affect the nutritional content of the egg.  It has also been questioned whether certain housing systems affect stress levels of the hens that may in turn, lead to changes in the nutrient content of an egg.

A recent study conducted by researchers at the USDA evaluated the nutrition content of eggs from hens raised under five different housing systems (including caged and free-range).  They also looked at the impact of the strain and age of the hen on nutrition quality.  In their first published paper from this study, they report on the mineral content of eggs of these different conditions. The age of the hen, the strain of the hen, and the conditions under which the hens are raised can result in small differences in the mineral content of the egg, but they aren’t a meaningful difference.

So what egg should I buy?  The answer to that question might be different for me than for you, but like they taught me in school--knowledge is power.

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