Author Archives: dianapan

Natural behaviours

The ability to perform natural behaviour is also a major concern of welfare as in some regards, it directly affects the affective state of the animal. Due to restrictions of space and limitations of equipment/substrates, hens are unable to carry out a wide range of natural behaviours (Bulmer and Gill, 2008) such as:

  • Scratching
  • Preening
  • Wing flapping/dust bathing
  • Body shaking
  • Feather rising
  • Nesting

Source: Tilly’s Nest

Source: Treats for Chicken

Cooper and Albentosa (2003) suggest that ground scratching, preening, and wing flapping are valued activities that are impaired by the high stocking densities in battery cages which make it physically impossible for birds to exhibit these behaviours due to lack of space. Additional comfort activities include body shaking and feather rising which are also not permitted by space (Nicol, 1987; Keeling, 1994). In a barren battery cage, laying hens are not able to demonstrate their natural behaviour of laying in a nest. Appleby et al. (1993) found in their study that almost all eggs (95 to 100%) were laid in nest boxes when provided.

Natural living requirements

The natural living requirements of a chicken include:

  • Omnivorous diet
  • Fresh water
  • Secure shelter
  • Light exposure
  • A flock

ballard-chicken-coopSource: Home Ecology

Hens need an omnivorous diet, known as ‘laying feed’ which they like to search for by scratching at soil. In addition, fresh water is required at all times. Further, as chickens are prey animals, they require secure shelter from predators. This shelter needs light exposure as hens lay based on daylight. Chickens should be housed in flocks as they are gregarious creatures. Specifically, hens take a communal approach to the incubation of eggs and raising their young.

However, even when natural living requirements are met, oftentimes the affective states of the animals are the next concern. This includes the lack of negative states like pain, distress, and suffering. In addition to that, many animal advocates believe that the animals’ emotions and feelings are just as important to consider when thinking of welfare (Fraser, 2008). However, it is difficult to identify and quantify certain affective states in animals as certain states cannot be observed directly. When there is no specific behaviour that accompanies an affective state, scientists may study changes in physiology as indirect evidence to prove certain states such as stress. Bulmer and Gill (2008) determined stress levels by measuring corticosterone concentrations in the eggs laid by hens housed in different farming systems. They found indications of chronic stress in battery hens. Further research shows hens in confinement experience severe frustration. However, it is also suggested that birds in battery cages are less likely to experience fear since they are housed in a stable social group with relatively few members. Regardless, around time of egg-laying, hens depict behaviours that may indicate pacing and increased aggression.


Alvery, D. M. & Tucker, S. A. (1994. Effect of cage floor mesh size and wire thickness on the foot condition of laying hens. In: Proceedings of the 9th European Poultry Conference, Glasglow, 280-281.

Appleby, M. C., S. F. Smith, and B. O. Hughes. 1993. Nesting, dustbathing and perching by laying hens in cages: effects of design on behaviour and welfare. British Poultry Science, 34: 835-847.

Appleby, M. C. 2004. What causes crowding? effects of space, facilities and group size on behaviour, with particular reference to furnished cages for hens. Animal Welfare, 13(3), 313-320.

Bell, D., 1995. A case study with laying hens. In Proceedings, Animal Behavior and the Design of Livestock and Poultry Systems International Conference (pp. 307-319). Northeast Regional Agricultural Engineering Service, Ithaca, NY.

Blount, W. P. (1968). Battery Cage Egg Production. In Intensive livestock farming (pp. 207-221). London: Heinemann Medical.

Bulmer, E., & Gil, D. 2008. Chronic stress in battery hens: Measuring corticosterone in laying hen eggs. International Journal of Poultry Science, 7(9), 880-883.

Cooper, J.J. & Albentosa, M. J. 2003. Behavioural needs in the domestic hen. Avian and Poultry Science Reviews 14, 127-149.

De Boer, IJM. and Cornelissen, A.M.G. 2002. A method using sustainability indicators to compare conventional and animal friendly egg production systems. Poultry Science 81:173-181.

Duncan, IJH. 2001. The pros and cons of cages. World’s Poultry Science Journal. 57:381-390.

Elson, A., & Tauson, R. 2011. Furnished cages for laying hens. Glasgow, UK.

Fraser, D. 2008. Understanding animal welfare: a science in its cultural context. Oxford, UK: Wiley-Blackwell.

Huber-Eicher, B. & Sebo, F. 2001. Reducing feather pecking when raising hen chicks in aviary systems. Applied Animal Behaviour Science 73, 59-68.

Keeling, L. J. 1994. Inter-bird distances and behavioural priorities in laying hens: the effect of spatial restriction. Applied Animal Behaviour Science 39, 131-140.

McAdie, T. M. & Keeling, L. J. 2002. The social transmission of feather pecking in laying hens: effects of environment and age. Applied Animal Behaviour Science 75, 147-159.

Moinard, C., Movisse, J. P. & Faure, J. M. 1998. Effect of cage area, cage hieght and perches on feather condition, bone breakage and mortality of laying hens. British Poultry Science 39, 198-202.

Nicol, C. J. 1987. Effect of cage height and area on the behaviour of hens housed in battery cages. British Poultry Science 28, 327-335.

Pohle, K., & Cheng, H. W. 2009. Furnished cage system and hen well-being: Comparative effects of furnished cages and battery cages on behavioral exhibitions in white leghorn chickens. Poultry Science, 88(8), 1559-1564.

Savage, T., & Darre, M. J. P. 2008. Internal parasites. (Fact Sheet). New Hampshire: University of New Hampshire.

Savory, CJ. 2004. Laying hen welfare standards: a classic case of ‘power to the people’. Animal Welfare. 13:S153-158.

Stevenson, P. 2004. European Union law and the welfare of farm animals (in International Animal Welfare Law Conference 2004, edited by Favre, D. and Hancock K.)

Street, B. R. M. S., P.Ag. (2012). The future of confinement housing for egg-laying hens. BC SPCA Farm Animal Welfare News: BC SPCA.

Tauson, R. (1998). Furnished cages and aviaries: Production and health. Poultry Science, 77(12).

Taylor, A. A. and Hurnik, J. F. 1994. The effect of long-term housing in an aviary and battery cages on the physical condition of laying hens: body weight, feather condition, claw length, foot lesions, and tibia strength. Poultry Science 73, 263-273.

Taylor, A.A. and Hurnik, J.F. 1996. The long term productivity of hens housed in battery cages and an aviary. Poultry Science. 75:47- 51.

Thaxton, J.P. 2004. Stress and the welfare of laying hens. In: Poultry Science Symposium Series 27.

Free range

The last alternative I will present and discuss is the free range housing system. Again, this is separate and distinct from the free run housing system. The definition that distinguishes free range from free run is that free range “provides birds with access to the outdoors when the climate permits, consequently, exposing these birds to sunlight” (National Farm Animal Care Council, 2003). In essence, the free range housing system is a free run housing system that also provides the extra outdoor access. Thus, within the indoor portions, the housing specifications are exactly the same, providing the hens with the same benefits.

7166328170_23d010c74a_bChandler, A. (Photographer). (2012, May 9). My backyard chickens [digital photo]. Retrieved from

However, one of the biggest acknowledgments that must be made is that free range systems only have to provide birds with access to the outdoors. Literature shows that for the most part, these systems are actually not extremely different from free run systems, save for some version of access to the outdoors – which does not necessarily promise grass or soil to forage at.

Some other disadvantages to this husbandry method include outside diseases that cannot be controlled or prevented (Savage, 2008).

Free run

The next alternative to conventional battery cages is the free run housing system. This system is separate and distinctive from the free range housing system. In a free run system, sometimes known as an “aviary”, hens are housed together in a large bun without cages. This husbandry method is similar to how broiler chickens are housed.

Aviary-01-1024x682Source: Egg Farmers of Alberta

Free run systems commonly have the following provisions:

  • Automated communal feeding systems
  • Litter flooring
  • Perches
  • Dust-bathing areas
  • Private nesting areas

While the added welfare benefits of increased movement/decreased restriction with the removal of the cage, there are also downsides to this housing method. For example, perhaps the most prominent disadvantage is the significantly increased ammonia and dust levels (Street, 2012).

Enriched cage

One practical alternative to battery cages is enriched cages. An enriched cage, sometimes called “furnished” or “modified” cage, is a wire cage with some specific design improvements to overcome some of the welfare concerns identified from the conventional battery cage. The practicality of the enriched cage is that it retains the same or similar husbandry and economic advantages of the conventional battery cage.

enriched_cagesSource: United Poultry Concerns

The estimated additional cost is an 8% difference in production costs (Elson and Tauson, 2011). With this extra marginal cost, hens housed in enriched cages are provided with:

  • Perches
  • Dust-bathing area
  • Private nesting area
  • Scratch pads

These items allow the hens to perform the natural behaviours which they are highly motivated to exhibit.

However, there are still criticisms to this improvement from battery cage housing. Some individuals believe that enriched cages still do not provide an adequate level of welfare.

Issues caused by battery cage rearing

When egg producers began using battery cages, they with met with varied basic health problems including injuries and feather damage that did not meet the natural living requirements of their hens (Fraser, 2008). As mentioned in a different section, Swedish scientist Ragnar Tauson who, alongside his colleagues, investigated the source of various basic health problems combatted by laying hens kept in battery cages.

Among these health issues identified were:

  • Significant foot lesions
    Source: Novus
  • Neck lesions
  • Overgrown claws
    Source: Animal Place Sanctuary
  • Loss of feathers
    Source: Little Hen Rescue

Tauson’s findings identified the cause of these health effects to be related to the battery cage housing system (Fraser, 2008).

Biological knowledge

Existing biological knowledge regarding welfare concerns incurred by laying hens housed in battery cages can be categorized under three main types:

  1. Natural living requirements
  2. Affective states
  3. Ability to exhibit natural behaviour.

Natural living requirements include basic health and functioning. This means that animals should be provided with adequate nutrients and shelter and protected from injury and disease. Ethical concerns regarding the affective states of laying hens recommend that animals should be free of negative states like pain, fear, discomfort and distress. Further, some advocates would extend this view beyond just the lack of negative states and suggest that animals should also be capable of experiencing normal pleasures and comforts. Lastly, the ability to perform important types and normal patterns of natural behaviour they are highly motivated to exhibit recommends that captive animals should be housed in an environment that is well suited to their species.

The natural living requirements of a chicken include an omnivorous diet, known as ‘laying feed’ which they like to search for by scratching at soil. In addition, fresh water is required at all times. Further, as chickens are prey animals, they require secure shelter from predators. This shelter needs light exposure as hens lay based on daylight. Chickens should be housed in flocks as they are gregarious creatures. Specifically, hens take a communal approach to the incubation of eggs and raising their young.

Welfare concerns

Despite the overwhelming prevalence of use through the globe, battery cages have been heavily criticized by animal welfare organizations and scientists (Taylor and Hurnik, 1996). Some even refer to the use of battery cages as ‘the cruelest’ of all factory farming practices (Stevenson, 2004).

6786428549_2943f0a88e_bSource: Sonin, J. (Photographer). (2012, January 29). Eye to eye [digital image]. Retrieved from:


While much of the European Union (and other select non-member European countries) as a whole proves to be more progressive in animal welfare legislation than other western countries such as those of North America, previous legislations of individual European countries displayed a dichotomy echoing contrasting attitudes (Appleby, 2003). For example, some European countries such as Sweden and Switzerland (a non-member of the EU) are considered as some of the leaders in animal welfare legislation of the developed world prior to the EU-wide ban of battery cages in 2012.

Switzerland was the first nation in the world to have banned laying cages (Appleby, 2003; Valkonen, 2010). A 1978 referendum, the Swiss Animal Welfare Act, allowed citizens, represented by 81 percent of the Swiss popular vote (Davis, 1996), to make the collective decision to impose the ban, effective by 1992.

Sweden took animal welfare matters into legislation in 1988 when it passed the new Animal Welfare Act which required starting the following year, all new cages must provide 600 cm2 or 93 in2 per hen. Further improvements and enrichment features, many of which were based on Tauson’s work mentioned above, of cages were also mandated by 1994. Shortly after, a new law called for battery cages to be outright banned by 1999. Further, the progressive country even went so far as to stipulate that alternative housing systems must not mean impaired animal health, increased medication, introduction of beak trimming or impaired working environment. However, the required conditions (Fredell (1994) suggested that alternative systems proved to be difficult) were inconsistent with the radical change (Abrahamsson, Tauson, and Appleby, 1995). The nation recognized arguments from the industry and opted to mandate enriched cages instead of the total ban (Tauson, 2000; Tauson and Holm, 2001).

The European Union Council Directive 1999/74/EC was passed in 1999 to ban conventional battery cages in the entire EU starting from January 1, 2012, recognizing a 13-year phase-out period (Studer, 46). As discussed above, at this time, this housing system was already banned in Switzerland and Sweden. Alongside the two countries already discussed, Germany, Austria, and the Netherlands also followed the same ban.

Comparatively, animal welfare legislation in western countries of North America pale in comparison. The battery cage is legal in Canada, where 98 percent of the country’s laying hens are housed (Baumel, 2005). While there is no formal legislation, the 2003 Recommended Code of Practice by the Canadian Agri-Food Research Council pushes for improved housing systems. Other non-government organizations like the Canadian Coalition for Farm Animals and the Vancouver Humane Society have continued to campaign for the Canadian Food Inspection Agency to adopt the EU’s policy. Most recently, a media release was issued by the Retail Council of Canada announcing that four grocery members, Loblaw Companies Limited, Metro Inc., Sobeys Inc., and Wal-Mart Canada Corp., voluntarily commit to source cage-free eggs by the end of 2025.

The case in the United States is not much different. The vast majority of laying hens in the United States are housed in battery cages. According to trade group United Egg Producers, only six percent of laying hens are currently raised without cages. The state of California passed a ballot proposition, Proposition 2, with 63 percent of the vote in the state’s general election in 2008. It called for standards for confirmed farming that required laying hens to be confined only in ways that allow these animals to lie down, stand up, fully extend their limbs and turn around freely to be effective by January 1, 2015. Similar to Canada, some independent retailers have voluntarily committed to source cage-free eggs. Last year, McDonald’s, the world’s largest fast food chain, has promised both its American and Canadian customers this transition over the next decade. Other large food suppliers including Costco, General Mills, and Burger King have also made similar announcements. Although there is no national legislation for the better welfare of laying hens in the United States, suppliers must meet the growing demand for cage-free eggs or they will lose their largest customers.