Free-range eggs

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A free-range egg purchased in the United Kingdom FreeRangeEgg.jpg
A free-range egg purchased in the United Kingdom

Free-range eggs are eggs produced from birds that may be permitted outdoors. The term "free-range" may be used differently depending on the country and the relevant laws, and is not regulated in many areas.

Contents

Eggs from hens that are only indoors might also be labelled cage-free, barn, barn-roaming or aviary, following the animal happiness certification policies, also known as "happy chickens" or "happy eggs". This is different from birds that are reared in systems labelled as battery cages or furnished cages .

Legal standards defining free range can be different or even non-existent depending on the country. Various watchdog organizations, governmental agencies and industry groups adhere to differing criteria of what constitutes "free-range" and "cage-free" status.

United States

The United States Department of Agriculture (USDA) requires that egg producers be able to demonstrate that "free range" egg layers have access to the outdoors, [1] though there is no government oversight as to the quality of the external environment, or the amount of time the hen has access to it. [2] Many producers label their eggs as cage-free in addition to, or instead of, free-range. [3] Recently, US egg labels have expanded to include the term "barn-roaming", to more accurately describe the source of those eggs that are laid by hens which can not range freely, but are confined to a barn instead of a more restrictive cage.

Debate

Commercial free-range hens outdoors Free Range Hens - geograph.org.uk - 342791.jpg
Commercial free-range hens outdoors
Commercial free-range hens indoors Free-range-hens.jpg
Commercial free-range hens indoors

Cage-free eggs have been a major cause of debate in the US. In 2015 there was an initiative proposed in Massachusetts that would ban the sale of in-state meat or eggs "from caged animals raised anywhere in the nation". This shift from caged to cage-free is concerning for egg industry groups because they believe that this will cause the price of eggs to increase to the point that consumers can not afford to buy them, thereby causing a decline in the egg industry overall. Animal welfare advocates argue that costs will not change as drastically as industry groups are expecting and that the price of eggs will remain almost the same because the housing of the birds does not make a huge difference to cost. Egg industry groups are making an effort to show or "educate lawmakers, voters and consumers about the merits and cost-effectiveness of cage use". Local farmers and producers say that the shift will occur if that is what consumers want, they will adapt to having birds in or out of cages. Not only are there debates between the egg industry and animal welfare advocates, but people are also debating whether this issue is one that has to be handled by the federal government or the industry. [4]

European Union

In the European Union, cage-free egg production includes barns, free-range, organic (in the UK, systems must be free-range if they are to be labelled as organic) and aviary systems. Non-cage systems may be single or multi-tier (up to four levels), with or without outdoor access. In the UK, free-range systems are the most popular of the non-cage alternatives, accounting for around 44% of all eggs in 2013, whereas barns and organic eggs together accounted for 5%. [5]

In free-range systems, hens are housed to a similar standard as the barn or aviary.

The European Union Council Directive 1999/74/EC stipulates that from 1 January 2007 (1 January 2012 for newly built or rebuilt systems), non-cage systems must provide the following:

In addition to these requirements, free-range systems must also provide the following:

Case studies of free-range systems for laying hens across the EU, carried out by Compassion in World Farming, demonstrate how breed choice and preventive management practices can enable farmers to successfully use non beak-trimmed birds. [6]

Australia

In 2012, Australian Eggs, the body for the industry, tried to register a free-range trademark allowing 20,000 hens per hectare on the range. This sparked a major discussion between large producers, small producers, animal welfare groups, and consumer rights groups. The trademark application was withdrawn after the Australian Competition & Consumer Commission commented that the "proposed standards may mislead consumers about the nature of eggs described as ‘free range’" in its Initial Assessment of the application. [7]

There is a voluntary code, which covers the basic standards of husbandry for physiological and behavioural needs of poultry, that allows for 1,500 layer hens per hectare. [8] However, the code also states that "any higher bird density is acceptable only when regular rotation of birds onto fresh range areas occurs". The voluntary code is under review and due to be consulted upon. [9]

The Queensland government approved an increase in free-range layer hen stocking densities in July 2013. The maximum number of hens per hectare was increased from 1,500 to 10,000. [10]

In March 2016, Australian ministers voted in new national standards for the definition of free-range. The new standards allow for up to 10,000 birds per hectare, with no requirement for the hens to actually go outside. [11] Choice, Australia's largest non-profit consumer organisation [12] believes Australia's consumer affairs ministers made the decision to put the interests of large-scale Australian egg producers ahead of the needs of consumers.

In April 2017, the Australian Government finalised the law and decided to mandate a maximum of 10,000 hens per hectare in outdoor grazing areas, to which the hens must have "regular and meaningful" access. [13] Currently, the most popular free range accreditation schemes mandating roaming space at or below the standard set by the EU for its members, are the Free Range Farmers Association (750 hens per hectare), [14] Humane Choice (1,500 hens per hectare) [15] and Australian Certified Organic (2,500 hens per hectare under pasture rotation). [16] In July 2017, Snowdale was fined a record amount of $1.05m (including legal costs) for falsely advertising that its eggs were 'free range'. [17] [18] This was substantially larger than the fines imposed upon Derodi, Holland Farms, Pirovic or Darling Downs Fresh Eggs; set at either $300,000 or $250,000. [19] [20] [21]

Cost

Based on data in the European Commission's socio-economic report published in 2004, [22] (prior to battery cages being banned in the EU) it cost €0.66 to produce 12 battery eggs, €0.82 to produce 12 barn eggs and €0.98 to produce 12 free-range eggs. This means that in 2004, one free-range egg cost 2.6 cents more to produce than a battery egg, and a barn egg cost 1.3 cents more to produce than a battery egg. The Commission's report concludes that, if costs were to increase by 20%, which it says is the type of percentage increase in terms of variable costs that producers are likely to face as a result of switching to free-range, the industry will potentially suffer a loss of producer surplus of €354 million (EU-25). [22] The margins achieved by producers for barn and free-range eggs are appreciably higher than those that were available for battery eggs. The Commission's socio-economic report shows that margins for free-range eggs were around twice as high as those for battery eggs. [22]

Animal welfare

Many animal welfare advocates, including the Humane Society of the United States maintain that cage-free and free-range eggs constitute a considerable improvement for laying hens. This has led to the adoption of a cage-free eggs standard by most major food companies in the United States, although in 2017, it was estimated cage-free eggs represented only 10% of all produced. [23] [24] Pundits and food commentators have described the 2016 shift toward cage-free eggs across the food industry as a "bold decision" and historic shift. [25] Several investigations, particularly by the animal rights group Direct Action Everywhere, have raised doubts about to what degree cage-free farms are an improvement for laying hens. [26] [27] An investigation of a cage-free Costco facility in late 2016 purported to find cannibalism from the birds attacking each other, and concluded that neither caged nor cage-free facilities offered laying hens positive lives. [28]

Misconceptions

Photograph of two hen egg yolks, one from a commercial egg operation and one from a free-range backyard hen. The yolk of the backyard egg is bright orange. Yolkcolor-10475164 1466594730270043 1278996929 n.jpg
Photograph of two hen egg yolks, one from a commercial egg operation and one from a free-range backyard hen. The yolk of the backyard egg is bright orange.

Free-range eggs may be broader and have more of an orange colour to their yolks [29] owing to the abundance of greens and insects in the birds' diet. However an orange yolk is no guarantee that an egg was produced by a free-range hen. Feed additives such as marigold petal meal, dried algae and alfalfa meal can be used to colour the yolks. [30]

Contrary to popular belief, in the United States free-range regulations do not necessarily require that hens spend substantial time outdoors, only that the hens "have access to the outdoors". [31] This access may be for very brief periods and the outside area may be small and sparse. Stocking densities indoors are often high, and many hens may stay inside as dominant hens often prevent the others from having access to the outside yard. [32]

Nutritional content

Differences in age, strain and nutrition of the hens make scientific conclusions about the effects of housing systems on the quality of the eggs exceedingly difficult. Consumer perceptions of these alternative systems delivering a better product are then scientifically unjustified in terms of there being any nutritional difference. [33] A 2011 research study carried out in North Carolina compared free-range and conventional caged eggs for fatty acids, cholesterol, vitamins A and E, finding higher fat content in free-range eggs, and no significant difference in cholesterol and vitamin levels. [34] Vitamin D in eggs has been observed to increase up to 4 times in hens that have exposure to sunlight, compared to hens that are kept away from sunlight. [35] Another research suggests that grass fed hens can produce eggs that are rich in (n−3) fatty acids, without adverse oxidative effects. [36] Some other non peer-reviewed studies have found evidence for nutritional benefit of free-range eggs. [37] [38] [39] [40]

Retailers

Several major retailers have a policy of selling only free-range eggs, or, not selling battery-cage eggs. Some retailers apply this policy not just to eggs in their shells, but also to eggs used in baked goods and processed products such as ready-made meals, quiches and ice cream. range shell eggs, and uses only free-range eggs in their processed products and ready-made meals. [6]

As of 1 January 2007 (with one minor exception), all Austrian supermarkets no longer sell battery eggs. Many retailers in the Netherlands, including Albert Heijn and Schuitema (subsidiaries of Ahold), Laurus (including Edah, Konmar and Super de Boer), Dirk van den Broek (including Bas van der Heijden and Digros), Aldi and Lidl sell only free-range shell eggs; however the free-range eggs that are sold in Aldi and Lidl do not meet some country's recommendations for the production of free-range eggs. Three Belgian supermarkets: Makro, Colruyt and Lidl, no longer sell battery eggs. The Commission's report states that Sweden's move away from conventional battery cages has been aided by the decision by the four largest retailers (who between them account for 98–99% of the Swedish retail market) to stop stocking conventional battery eggs. [22] U.S. food suppliers Aramark and Unilever have announced they intend to buy only cage-free eggs, but as of 2013 there are not enough available to supply them. [41]

In Australia free-range eggs that are sold in Aldi and Lidl do not meet the CSIRO's Model Code recommendation of 1,500 hens per hectare. In March 2016, Australian ministers voted in new standards for the definition of free-range. The new standards allow for up to 10,000 birds per hectare, with no requirement for the hens to actually go outside. [11] Choice, Australia's largest non-profit consumer organisation [12] believes Australia's consumer affairs ministers made the decision to put the interests of large-scale Australian egg producers ahead of the needs of consumers. A group called PROOF (standing for Pasture Raised On Open Fields) is now in the process of developing an accreditation scheme which will see the term "pastured" start appearing on cartons. The guidelines for PROOF's pastured eggs allow for a maximum stocking density of 1500 birds per hectare (in line with the CSIRO Model Code) as well as requiring that hens are able to range freely in open fields or paddocks. So far, PROOF has 12 licensed egg farms in Australia, with another eight in the pipeline. [11]

Environmental impact

Free range eggs carry an environmental cost. This is mainly because in free range egg production systems, the habitat is difficult to control and the resource required to produce eggs is higher than in caged egg production. A study done in the University of Newcastle, UK, showed a 16% increase in greenhouse gas emissions from a free range facility compared to a battery cage facility. [42]

Rehoming charities

Rescue hens (red) and point-of-lay hens (dark) co-exist in a private orchard. Poolfield orchard.jpg
Rescue hens (red) and point-of-lay hens (dark) co-exist in a private orchard.

In the UK, charities such as Fresh Start for Hens [43] and British Hen Welfare Trust [44] organise rehoming for ex-factory hens that would otherwise be slaughtered. Private smallholders pay around £6 per "rescue hen", and these birds (which may still be laying daily) then spend a "retirement" in a true free-range environment. The BHW Trust says that there is no better education than watching an ex-battery hen's confusion and bewilderment turn into wonderment at her new environment.

See also

Related Research Articles

<span class="mw-page-title-main">Poultry</span> Domesticated birds kept by humans for their eggs, meat, or feathers

Poultry are domesticated birds kept by humans for the purpose of harvesting animal products such as meat, eggs or feathers. The practice of raising poultry is known as poultry farming. These birds are most typically members of the superorder Galloanserae (fowl), especially the order Galliformes. The term also includes waterfowls of the family Anatidae but does not include wild birds hunted for food known as game or quarry.

<span class="mw-page-title-main">Debeaking</span> Trimming of a birds beak, usually performed on domesticated birds

Debeaking, beak trimming, or beak conditioning, is the partial removal of the beak of poultry, especially layer hens and turkeys, although it may also be performed on quail and ducks. Most commonly, the beak is shortened permanently, although regrowth can occur. The trimmed lower beak is somewhat longer than the upper beak. A similar but separate practice, usually performed by an avian veterinarian or an experienced birdkeeper, involves clipping, filing or sanding the beaks of captive birds for health purposes – in order to correct or temporarily to alleviate overgrowths or deformities and better allow the bird to go about its normal feeding and preening activities. Amongst raptor-keepers, this practice is commonly known as "coping".

<span class="mw-page-title-main">Pastured poultry</span>

Pastured poultry is a sustainable agriculture technique that calls for the raising of laying chickens, meat chickens (broilers), guinea fowl, and/or turkeys on pasture, as opposed to indoor confinement. Humane treatment and the perceived health benefits of pastured poultry are causing an increase in demand for such products.

Australian Eggs (AE) is the major marketer of eggs in Australia. It is a producer-owned corporation, representing approximately 400 commercial egg producers and is based in Sydney. The activities of AE include marketing, research and development, and policy services. According to its website, it runs public awareness campaigns on animal welfare, nutrition, and vaccine development. However, it has received criticism from animal welfare organisations for using these terms for promotional purposes. The corporation is affiliated with the International Egg Commission (IEC).

<span class="mw-page-title-main">Free range</span> Method of farming where animals can roam freely outdoors

Free range denotes a method of farming husbandry where the animals, for at least part of the day, can roam freely outdoors, rather than being confined in an enclosure for 24 hours each day. On many farms, the outdoors ranging area is fenced, thereby technically making this an enclosure, however, free range systems usually offer the opportunity for the extensive locomotion and sunlight that is otherwise prevented by indoor housing systems. Free range may apply to meat, eggs or dairy farming.

<span class="mw-page-title-main">Battery cage</span> Agricultural technology

Battery cages are a housing system used for various animal production methods, but primarily for egg-laying hens. The name arises from the arrangement of rows and columns of identical cages connected, in a unit, as in an artillery battery. Although the term is usually applied to poultry farming, similar cage systems are used for other animals. Battery cages have generated controversy between advocates for animal welfare and industrial producers.

<span class="mw-page-title-main">Organic egg production</span>

Organic egg production is the production of eggs through organic means. In this process, the poultry are fed organic feed. According to the United States Department of Agriculture, organic means that the laying hens must have access to the outdoors and cannot be raised in cages. Only natural molting can occur within the flock; forced molting is not allowed. Organic certification also requires maintenance of basic animal welfare standards.

<span class="mw-page-title-main">Intensive animal farming</span> Branch of agriculture

Intensive animal farming, industrial livestock production, and macro-farms, also known as factory farming, is a type of intensive agriculture, specifically an approach to animal husbandry designed to maximize production while minimizing costs. To achieve this, agribusinesses keep livestock such as cattle, poultry, and fish at high stocking densities, at large scale, and using modern machinery, biotechnology, and global trade. The main products of this industry are meat, milk and eggs for human consumption. There are issues regarding whether intensive animal farming is sustainable in the social long-run given its costs in resources. Analysts also raise issues about its ethics.

<span class="mw-page-title-main">Yarding</span> Provision of a fenced yard in poultry keeping


In poultry keeping, yarding is the practice of providing the poultry with a fenced yard in addition to a poultry house. Movable yarding is a form of managed intensive grazing.

<span class="mw-page-title-main">Poultry farming</span> Part of animal husbandry

Poultry farming is the form of animal husbandry which raises domesticated birds such as chickens, ducks, turkeys and geese to produce meat or eggs for food. Poultry – mostly chickens – are farmed in great numbers. More than 60 billion chickens are killed for consumption annually. Chickens raised for eggs are known as layers, while chickens raised for meat are called broilers.

The British Hen Welfare Trust (formerly the Battery Hen Welfare Trust) is the United Kingdom's first registered charity solely for laying hens. It was founded in April 2005 by Jane Howorth, and was established in order to raise awareness of the 20 million hens kept in cages in the UK at that time. Its activities include collecting hens which have reached the end of their commercial lives and re-homing them as pets. The charity's headquarters are near Rose Ash, North Devon.

<span class="mw-page-title-main">2008 California Proposition 2</span> California ballot proposition

Proposition 2 was a California ballot proposition in that state's general election on November 4, 2008. It passed with 63% of the votes in favor and 37% against. Submitted to the Secretary of State as the Prevention of Farm Animal Cruelty Act, the initiative's name was amended to officially be known as the Standards for Confining Farm Animals initiative. The official title of the statute enacted by the proposition is the Prevention of Farm Animal Cruelty Act.

<span class="mw-page-title-main">Poultry farming in the United States</span>

Poultry farming is a part of the United States's agricultural economy.

<span class="mw-page-title-main">Feather pecking</span> When one bird repeatedly pecks at the feathers of another

Feather pecking is a behavioural problem that occurs most frequently amongst domestic hens reared for egg production, although it does occur in other poultry such as pheasants, turkeys, ducks, broiler chickens and is sometimes seen in farmed ostriches. Feather pecking occurs when one bird repeatedly pecks at the feathers of another. The levels of severity may be recognized as mild and severe. Gentle feather pecking is considered to be a normal investigatory behaviour where the feathers of the recipient are hardly disturbed and therefore does not represent a problem. In severe feather pecking, however, the feathers of the recipient are grasped, pulled at and sometimes removed. This is painful for the receiving bird and can lead to trauma of the skin or bleeding, which in turn can lead to cannibalism and death.

Vent pecking is an abnormal behaviour of birds performed primarily by commercial egg-laying hens. It is characterised by pecking damage to the cloaca, the surrounding skin and underlying tissue. Vent pecking frequently occurs immediately after an egg has been laid when the cloaca often remains partly everted exposing the mucosa, red from the physical trauma of oviposition or bleeding if the tissue is torn by her laying an egg. Vent pecking clearly causes pain and distress to the bird being pecked. Tearing of the skin increases susceptibility to disease and may lead to cannibalism, with possible evisceration of the pecked bird and ultimately, death.

<span class="mw-page-title-main">Cannibalism in poultry</span>

Cannibalism in poultry is the act of one individual of a poultry species consuming all or part of another individual of the same species as food. It commonly occurs in flocks of domestic hens reared for egg production, although it can also occur in domestic turkeys, pheasants and other poultry species. Poultry create a social order of dominance known as pecking order. When pressure occurs within the flock, pecking can increase in aggression and escalate to cannibalism. Cannibalism can occur as a consequence of feather pecking which has caused denuded areas and bleeding on a bird's skin. Cannibalism can cause large mortality rates within the flock and large decreases in production due to the stress it causes. Vent pecking, sometimes called 'cloacal cannibalism', is considered to be a separate form of cannibalistic pecking as this occurs in well-feathered birds and only the cloaca is targeted. There are several causes that can lead to cannibalism such as: light and overheating, crowd size, nutrition, injury/death, genetics and learned behaviour. Research has been conducted to attempt to understand why poultry engage in this behaviour, as it is not totally understood. There are known methods of control to reduce cannibalism such as crowd size control, beak trimming, light manipulation, perches, selective genetics and eyewear.

<span class="mw-page-title-main">Furnished cage</span>

A furnished cage, sometimes called enriched cage, colony cage or modified cage, is a type of cage used in poultry farming for egg laying hens. Furnished cages have been designed to overcome some of the welfare concerns of battery cages whilst retaining their economic and husbandry advantages, and also provide some of the welfare advantages over non-cage systems. Many design features of furnished cages have been incorporated because research in animal welfare science has shown them to be of benefit to the hens.

<span class="mw-page-title-main">Directive 1999/74/EC</span>

Directive 1999/74/EC is legislation passed by the European Union on the minimum standards for keeping egg laying hens which effectively bans conventional battery cages. The directive, passed in 1999, banned conventional battery cages in the EU from 1 January 2012 after a 13-year phase-out. Battery cages were already banned in Germany, Austria, the Netherlands and Sweden prior to 2012. The directive does not apply to establishments with fewer than 350 laying hens or establishments rearing breeding laying hens. Such establishments are, however, subject to the requirements of Directive 98/58/EC. The directive is not supported with fines, penalties or export bans.

<span class="mw-page-title-main">Egg marking</span>

Egg marking is a form of egg labelling that includes an egg code stamped on the egg itself. In the EU there is a producer code regulated by law since 2004. It allows consumers to distinguish free range eggs and organic farming eggs from the industrial caged hen production.

<span class="mw-page-title-main">Broiler industry</span> Process by which broiler chickens are reared and prepared for meat consumption

The broiler industry is the process by which broiler chickens are reared and prepared for meat consumption. Worldwide, in 2005 production was 71,851,000 tonnes. From 1985 to 2005, the broiler industry grew by 158%.

References

  1. "Meat and Poultry Labeling Terms". fsis.usda.gov. United States Department of Agriculture: Food Safety and Inspection Service . Retrieved 12 October 2015.
  2. Kelso, Anders (23 December 2013). "Farm Fresh? Natural? Eggs Not Always What They're Cracked Up To Be". NPR . National Public Radio . Retrieved 12 October 2015.
  3. "Why Free Range Eggs". Bag of Greens. Retrieved 15 February 2021.
  4. "Egg industry yielding in cage-free fight". Politico . 21 September 2015. Retrieved 15 October 2015.
  5. UK egg production and price statistics Department for Environment, Food & Rural Affairs
  6. 1 2 3 4 Compassion in World Farming report - Alternatives to the barren battery cage
  7. Commission, Australian Competition and Consumer (21 January 2013). "Australian Egg Corporation CTM 2012". Australian Competition & Consumer Commission . Retrieved 13 August 2017.
  8. Committee., Primary Industries Standing (2002). Domestic poultry (4th ed.). Collingwood, Vic.: CSIRO. ISBN   9780643068674. OCLC   52868483.
  9. Burgess, Elise (5 August 2017). "Poultry code review could help unscramble rules allowing cruelty to chickens". Sydney Morning Herald . Retrieved 13 August 2017.
  10. "'Free range eggs' definition scrambled". Brisbane Times . 29 July 2013. Retrieved 22 February 2019.
  11. 1 2 3 "Ministers make free-range egg labelling meaningless". Choice . 31 March 2016. Retrieved 22 February 2019.
  12. 1 2 "The CHOICE story". Choice . Retrieved 22 February 2019.
  13. Pearce, Lara (28 April 2017). "This Is What The Government's New 'Free Range' Egg Guidelines Look Like". Huffington Post . Retrieved 13 August 2017.
  14. "Hen Welfare". Free Range Farmers Association Inc. Retrieved 13 August 2017.
  15. "Free Range Standards | Pork, Beef, Lamb, Chicken". www.humanechoice.com.au. Retrieved 13 August 2017.
  16. "FAQs". austorganic.com. Retrieved 13 August 2017.
  17. "Record fine for 'free range' egg farmer Snowdale". The Australian . Retrieved 13 August 2017.
  18. "Egg producer handed 'record' fine over false free-range labelling". ABC News . 25 July 2017. Retrieved 13 August 2017.
  19. "Free Range Egg Farms ordered to pay $300,000 penalty for false or misleading "free range egg" claims". Australian Competition & Consumer Commission. 14 April 2016. Retrieved 13 August 2017.
  20. "Federal Court orders $250,000, penalty against Darling Downs Fresh Eggs for misleading 'free range' claims". Australian Competition & Consumer Commission. 14 September 2015. Retrieved 13 August 2017.
  21. Commission, Australian Competition and Consumer (23 September 2014). "Federal Court orders $300,000 penalty after finding 'free range' egg claims to be misleading". Australian Competition & Consumer Commission. Retrieved 13 August 2017.
  22. 1 2 3 4 European Commission, 2004. Study on the socio-economic implications of the various systems to keep laying hens.Final Report for The European Commission, submitted by Agra CEAS Consulting Ltd., 2120/CC/December 2004. in Compassion in World Farming report - Alternatives to the barren battery cage
  23. "Cage-Free vs. Battery-Cage Eggs : The Humane Society of the United States". www.humanesociety.org. Retrieved 8 May 2017.
  24. Wong, Vanessa (22 March 2017). "Egg makers are freaked out by the cage-free future". CNBC. Retrieved 8 May 2017.
  25. "Inside McDonald's Bold Decision to Go Cage-Free". Fortune . Retrieved 8 May 2017.
  26. Strom, Stephanie (20 October 2016). "How 'Cage-Free' Hens Live, in Animal Advocates' Video". New York Times . ISSN   0362-4331 . Retrieved 8 May 2017.
  27. "California Hens Can Now Stretch Their Wings, but Will They Ever Fly?". Pacific Standard. Retrieved 8 May 2017.
  28. Hsiung, Wayne (21 October 2016). "'They're Being Eaten Alive!' What I Saw In A Cage-Free Egg Farm". Huffington Post. Retrieved 8 May 2017.
  29. Van Den Brand H, Parmentier HK, Kemp B (2004). "Effects of housing system (outdoor v. cages) and age of laying hens on egg characteristics". Br. Poult. Sci. 45 (6): 745–52. doi:10.1080/00071660400014283. PMID   15697013. S2CID   26468071.
  30. North, M. and Bell, D. Commercial Chicken Production Manual, page 678. Van Nostrand Reinhold, 1990
  31. "Turkey raised by the rules". USDA. Retrieved 24 September 2015.
  32. UPC report
  33. Nys, Yves; Bain, Maureen; Immerseel, Filip Van, eds. (2011). Impossible the safety and quality of eggs and egg products. Cambridge: Woodhead. pp. 318–319. ISBN   978-0857093912.
  34. Anderson, K. E. (14 June 2011). "Comparison of fatty acid, cholesterol, and vitamin A and E composition in eggs from hens housed in conventional cage and range production facilities". Poultry Science. 90 (7): 1600–1608. doi: 10.3382/ps.2010-01289 . PMID   21673178.
  35. Kühn, Julia; Schutkowski, Alexandra; Kluge, Holger; Hirche, Frank; Stangl, Gabriele I. (1 April 2014). "Free-range farming: A natural alternative to produce vitamin D-enriched eggs". Nutrition. 30 (4): 481–484. doi:10.1016/j.nut.2013.10.002. ISSN   0899-9007. PMID   24607306.
  36. Lopez-Bote, C.J; Sanz Arias, R; Rey, A.I; Castaño, A; Isabel, B; Thos, J (May 1998). "Effect of free-range feeding on n−3 fatty acid and α-tocopherol content and oxidative stability of eggs". Animal Feed Science and Technology. 72 (1–2): 33–40. doi:10.1016/S0377-8401(97)00180-6.
  37. Jull, Morley A. Successful Poultry Raising. 1943
  38. Karsten, Heather. "Pasture-ized Poultry." Penn State Online Research," May 2003. http://www.rps.psu.edu/0305/poultry.html Archived 1 September 2006 at the Wayback Machine
  39. Long, C. and Newbury, U. "The Good Egg." Mother Earth News, August/September 2005. http://www.motherearthnews.com/DIY/2005-08-01/The-Good-Egg.aspx
  40. Long, C. and Alterman, T. "Meet Real Free-Range Eggs" Mother Earth News, October/November 2007. http://www.motherearthnews.com/Whole-Foods-and-Cooking/2007-10-01/Tests-Reveal-Healthier-Eggs.aspx
  41. Dan Charles (27 June 2013). "What The Rise of Cage-Free Means For Chickens". NPR.
  42. Leinonen, Ilkka (October 2013). "Quantifying the environmental impacts of UK broiler and egg production systems". Lohmann Information. 48 (2): 45–50 via Deutsche National Bibliothek.
  43. "FSFH site". Archived from the original on 7 September 2016. Retrieved 9 September 2016.
  44. BHWT site