Welfare and Production Benefits of Laying Hens in Enriched vs. Conventional Caging Systems

By: Lindsey Youngman, Kristina O’Keefe, and Casey Sullivan


Laying hens housed in a typical battery cagehttp://upload.wikimedia.org/wikipedia/commons/thumb/0/03/Animal_Abuse_Battery_Cage_01.jpg/220px-Animal_Abuse_Battery_Cage_01.jpg

Laying hens housed in a typical battery cage       Retrieved from: http://upload.wikimedia.org/wikipedia/commons/thumb/0/03/Animal_Abuse_Battery_Cage_01.jpg/220px-Animal_Abuse_Battery_Cage_01.jpg




The stench of decaying flesh filled the air as an undercover investigator by the name of “Scott” walked between the rows of battery cages at Sparboe Farms in Iowa. Rats darted across the egg plates and flies swarmed the chickens, feasting on a meal of a long deceased hen. He watched as other workers grabbed hens by the neck, slamming them in and out of cages too small for movement. The cages extended the length of two football fields, each festering with vermin and decay (Ross, 2011). Above all the rot, however, were innocent lives being held captive in the most inhumane conditions.

In 2011 an animal activist group called Mercy for Animals conducted an undercover investigation into McDonald’s leading egg supplier, Sparboe Farms. The Iowa farm had been in business for over 50 years, but recent concerns regarding animal rights and welfare violations brought investigators to the scene. What they discovered not only violated animal welfare rights, but also posed as a “public health threat” according to David Etcheson, the former head of public safety during the Bush administration. Thousands of hens were housed in an elaborate system of battery cages, each contaminated with dead birds, rats, and flies. Conditions were so serious that the FDA issued a rare letter to the owner stating that their farm had “…serious significant violations…” with sanitary conditions at five different branches of their farm. These violations were serious enough to lead to contaminated eggs that could harm consumers, and the abusive videos launched by ABC News showing hens being swung around by the neck on a piece of rope for fun were enough to influence McDonald’s to find an entirely new egg supplier (Ross, 2011).

Battery cages are both unnecessary and inhumane systems of housing used by commercial egg producers. Hens housed in these systems are crammed into wire cages that are about eighteen to twenty inches long and wide. Ten birds are crammed into a single cage, with each hen only having space about the size of a standard piece of printer paper to herself. The cages are stacked on top of each other, allowing for thousands of birds to be housed in the same building (Barlett, n.d.). In the case of Sparboe Farms and countless other commercial operations, these confined cages limit the natural behaviors of the hens and violate animal welfare rights, and also puts the consumer at risk for disease due to unsanitary conditions. Alternatives to battery cages are furnished cages. Furnished cage systems, also called enriched housing systems or colony cages, are cages for egg laying hens that reduce welfare concerns and allow hens to express natural behaviors. A typical cage houses forty to eighty hens, however there is substantial space for the hens to move around. Each hen has a nesting site, scratchpads for scratching and pecking, fifteen centimeter long perches for perching, food troughs for foraging, and a claw and beak-trimming surface for physical maintenance. These features allow the hens to express natural behaviors that not only benefit them behaviorally and emotionally, but physiologically as well.

Most egg producers who use battery cages believe that they are the most efficient method of egg production and deny any welfare concerns. The owner of Sparboe Farms claimed that the battery cage system is both “…cost efficient…” and “…scientifically acceptable…”, despite the graphic footage that was taken directly from his farm and released to the public (Ross, 2011). Farm busts like the one that occurred in Iowa should act to raise awareness in the minds of commercial producers all over the United States.

Public Health Concerns

Public safety should also be considered, as the unavoidable vermin that comes with a poorly managed production facility leads to feces contaminating feed with salmonella, which goes on to contaminate the chickens, their eggs, and therefore the consumer (Ross, 2011). A common argument of producers is that battery cages provide the most efficient system for housing laying hens in order to prevent “floor eggs”, which are eggs that are laid on the floor and are more likely to be contaminated by feces. They argue that battery cages allow the eggs to roll to a secure egg plate free from fecal debris. The truth is furnished cages, rather than battery cages, do not produce “floor eggs” in large enough numbers for it to be a significant disadvantage. Taylor and Hurnik (1996) support this claim with the results from their study, which shows that only 2.5% of eggs from furnished systems in the current study were laid on the floor in Year 1, and 0.3% of eggs were laid on the floor in Years 2 and 3. Overall, 1.7% of eggs were laid on the floor during the entire duration of the study. Egg production practices can be improved benefitting both the producer and the consumer simply by switching to an alternative caging system such as furnished cages.

Physiological Welfare Implications

The following analogy given by Bruce Friedrich, Director of Strategic Initiatives for Farm Sanctuary, gives only a small window into the detailed, welfare compromising experiences that laying hens kept in conventional battery cages undergo for the duration of their lifespan:

To get a sense of a hen’s life in a battery cage, imagine spending your entire life in a wire cage the size of your bathtub with four other people. You wouldn’t be able to move, so your muscles and bones would deteriorate. Your feet would become lacerated. You would go insane. That’s precisely what happens to laying hens (Friedrich, 2013).

Limiting the amount of movement for birds in the extremities of a battery cage causes major reductions in bone strength and density, which more often than not lead to cases of untreated osteopenia and bone breakages.  The lack of perches in conventional cages has shown to be a huge factor in such cases.  Studies done by Hughes and others (1993) and Hughes and Appleby (1989) proved that hopping up and down from perches allowed stress to the leg bones of the hens, therefore stimulating the increase of bone mass and bone strength in the birds.  This naturally makes for less bone breakages and cases of osteopenia (Baxter, 1994).  Tactacan et al. (2009) also performed a study that further supported this claim.  In their research, they found that hens in enriched cages (i.e. including a perch and more space) had significantly higher bone mineral densities of the tibia and humerus than birds that were confined to battery cages.

However, the negative effects of restricted movement is not limited to just the legs of the birds.  Reductions in overall bone strength of hens housed in battery cages have been as extreme as 23% to 45% when compared with birds in furnished cages (Baxter, 1994).  Extremities of such cases have been termed “cage fatigue” and are accompanied by grossly cascading effects. “Some birds’ skeletal systems become so weak that their spinal cords deteriorate and they become paralyzed; the animals then die from dehydration in their cages … investigation after investigation finds living birds forced to stand on the rotting, mummified carcasses of their dead cage-mates” (Friedrich, 2013).

Unfortunately, the negative effects of overcrowding and lack of enrichment do not stop there.  Not only do these factors contribute to physiological impairments to the birds, but their emotional well being also deteriorates.  Chickens are extremely hierarchical animals in nature, known to be brutal in establishing their pecking orders.  In addition chickens are cannibalistic, and their cannibalistic behaviors are triggered by frustration and seeing the color red. This can can be detrimental if a hen starts to bleed or lose feathers, exposing their reddish skin.  For these reasons, perches are not only used as a means of exercise, but they are also utilized as an effective route for avoiding aggression.  Research done by Hughes and Wood-Gush (1977) and Hughes and Appleby (1989) found that perches provide refuge for subordinate hens, and that hens housed in furnished cages including a perch were significantly less aggressive than caged hens because they were allowed access to quite literally stay in their place amongst the flock (Baxter, 1994).

The poor physical welfare implications battery cages have on laying hens continue on.  More obvious visible injuries can be detected on the birds via simple observation with the naked eye.  The feet lacerations Friedrich mentioned in his analogy are painfully accurate to the realities that battery cage victims are subject to regularly.  The average time a hen spends in a single battery cage is approximately two to three years.  This means two to three years standing with their entire body weight supported on two raw feet directly adjacent with metal wire.  Unsurprisingly, idle battery caged hens, unable to move off of the metal grates to relieve themselves from contact with the hard, rough surface have extremely high instances of painful open toe lesions when compared to those in enriched caging systems.  This condition is commonly referred to as “bumblefoot”.  As if broken feet and open wounds were not enough, it is common for birds in battery cages to have severely overgrown claws (Taylor and Hurnik, 1996).  Such cases do not prove to be an issue for hens housed in furnished cages complete with claw trimming surfaces that keep up with healthy maintenance of the birds’ toes.

Behavioral Welfare Implications

The mental welfare of the hens is compromised when the basic needs for social and spatial stimuli are not being met. Battery cages do not provide chickens with the resources to live lives that allow them to act natural according to their biological needs. These confined areas provide them with no room to perform their full range of natural behaviors, which keeps the mental state of the hens at bay. Results of studies by Nicol (1987), Knowles and Broom (1990), and Norgaard-Nielson (1990) concluded that wing flapping (an instinctual behavior) is completely inhibited in battery cages, and that several comfort behaviors such as head stretching, feather raising, and body shaking are significantly reduced. Not allowing for even small amounts of movement is depriving the chickens of their basic needs in achieving a stressless life.  They are also deprived of a nesting area, which the birds use as an area to comfortably lay their eggs in. Not being provided a location in which they feel comfortable to lay causes the chickens stress and can be detected physiologically in cases of hens withholding eggs. Studies by Duncan (1970) and Kite (1985) proved that hens without a place to nest will retain their eggs for up to 24 hours, only to lay them within minutes of returning to pens where nest boxes are provided.  Not only is this a welfare issue, but this could also have poor implications from a production standpoint as well.

In the absence of nesting sites, chickens also show behavioral effects detrimental to their mental state. For example, the hens begin to perform “vacuum behaviors”, which are artificial attempts at performing actions that they instinctually feel the need to complete when they are denied the ability to do so. This causes them to continuously go through the motions of a natural behavior, or attempt to do so repeatedly.  Studies performed by Wood-Gush (1972), Wood-Gush (1975), Wood-Gush and Gilbert (1969), Mills and Wood-Gush (1985), and Kite (1985), have all shown that hens without nesting grounds have prolonged searching behaviors, display higher restlessness, attempt to escape more often, or sit and perform vacuum nesting behaviors – all signs of frustration in the birds.

In contrast, furnished cages aim to achieve the opposite.  As Appleby (1993) described:

“The furnishings contained within the colony cages are intended to enable the birds to express a range of behaviors considered most important to the birds. Colony cages therefore attempt to combine the benefits of the cage system by maintaining the levels of hygiene and productivity with the behavioral freedoms afforded by non-cage systems”.

Production/Case Studies

In terms of human dimensions, one of the biggest concerns for farmers is the cost of the housing and maintenance facilities for the production hens.  One of the largest expenses comes from feeding the animals.  A common misconception is that if the hens move less and live in a warmer environment (i.e. are in a restricting, small location), then they will burn less energy and require less feed.  Therefore, there is an assumption that hens housed in areas where they are allowed room to exercise will burn more energy staying active and warm, and therefore will require more feed.  However, this has proven not to be the case.  Tactacan et al. (2009) performed a study that proved that feed consumption did not vary between enriched and conventional caging systems. The authors described how built-in ventilation fans and convection heaters commonly  included in enriched caging operations reduced the need for thermoregulation by the hens, thereby conserving energy resulting in no increase of feed consumption, and henceforth no increase in feed costs.

Further proof that enriched cages do not require overall higher expenses than battery cages can be obtained from data on the furnished cages of New Zealand.  Studies performed on New Zealand’s housing facilities by Abrahamsson et al. (1995) and Guesdon and Faure (2004) have shown that from a commercial perspective, most colony cages have provided similar production and feed conversion results as battery cages.   Although different studies have shown that egg production and feed conversion were higher in battery cages than colony cages , these studies also found that bird mortality was lower in the furnished cages, therefore the  total egg output ended up to be extremely similar in both conventional and furnished systems (Ministry of Agriculture and Forestry, 2011). In both instances, production rates were not compromised through the use of enriched caging systems.  This information is especially meaningful when considering the United States because New Zealand and the United States have a very similar ratio of number of eggs consumed per adult, proving to be a fantastic case study that a switch over from battery cages to furnished cages can eventually be accomplished in the United States with no production losses.

Another monetary concern facing producers is the price of installing furnished cages.  Even though it is difficult to assess exact costs of installing such systems in commercial industry, the cost of installing two experimental systems, one battery and the other furnished, were comparable in a study done in an 800 bird setting (Taylor and Hurnik, 1996).  Although this sample size is considerably smaller than a full-scale operation, the changes can still be done with economic efficiency, as seen in large-scale changes of the same nature that have already been put into effect in New Zealand, Europe, Michigan, California, and various other countries. (Ministry of Agriculture and Forestry, 2011).


Battery cages have not only proved to be unnecessary, but have also proved to be inhumane in both practice and execution. Improper management techniques make these already suffocating conditions even more dire, compromising the well being of both the hens and the consumers. Furnished cage systems offer hens space to move around, area to spread their wings, and area to perform natural behaviors such as pecking, nesting, and dust bathing. The best option for the hens, consumers, and producers is to stop the use of battery cages, and convert all commercial operations to furnished cage systems. Increased bone density and overall quality of life are just a few things that improve for laying hens housed in enriched cages with no cost to the producer. New Zealand, California, Michigan, and most of Europe have already made the humane and economical choice to ban battery cages benefiting the consumer, producer, and most importantly the laying hens. By implementing laws that establish the large space and new enrichment requirements for hens that furnished cages offer, battery cages could effectively be banned in the near future, preventing commercial egg laying companies from undergoing harsh criticisms by the FDA and losing major accounts like McDonalds. Gandhi once said, “The greatness of a nation can be judged based on how they treat their animals”. In a society striving for innovation and progress, it is time we take a step back, open up our eyes, and begin to make changes that benefit the common good.


Abrahamsson, P., Tauson, R and Appleby, M.C. (1995). Performance of four hybrids of laying hens in modified and conventional cages. Acta Agriculturae Scandinavica 45 (4), 286-296.


Barlett, J., (n.d.). Battery Egg Campaign. Retrieved from Wesleyan University Environmental Organizer’s Network website: http://www.wesleyan.edu/wsa/warn/eon/index.html


Baxter, M. R. (1994, June 11). The welfare problems of laying hens in battery cages. Veterinary Record, 134(24), 614-619. Retrieved from Agricola


Farm sanctuary. (n.d.). State legislation. Retrieved from:                  http://www.farmsanctuary.org/get-involved/federal-legislation/state-legislation/

Friedrich, B. (2013, January 17). The cruelest of all factory farm products: eggs from caged hens. Retrieved from http://blog.farmsanctuary.org/2013/01/the-cruelest-of-all-factory-farm-products-eggs-from-caged-hens/


Ministry of Agriculture and Forestry (New Zealand) (2005). Animal Welfare (Layer Hens) Code of Welfare, Ministry of Agriculture and

Forestry, Wellington, New Zealand


Ministry of Agriculture and Forestry (New Zealand).  (2011). Evaluation of furnished cage systems for the New Zealand egg market. Final

Report. Sustainable Farming Fund for the Ministry of Agriculture and Forestry



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. Retrieved from Agricola doi: 10.3382/ps.2009-00045


Ross, B., narrator. (2011, November 19). Egg farms. 20/20.  ABC News.


Shields, S., & Duncan, I.J.H. (n.d.). An HSUS report: a comparison of the welfare of hens in battery cages and alternative systems. Retrieved from http://www.humanesociety.org/assets/pdfs/farm/hsus-a-comparison-of-the-welfare-of-hens-in-battery-cages-and-alternative-systems.pdf

Tactacan, G. B., Rodriguez-Lecompte, J. C., House, J. D., Guenter, W. W., & Lewis, N. J. (2009). Performance and welfare of laying hens in conventional and enriched cages. Poultry Science, 88(4), 698-707. Retrieved from Agricola.

Taylor, A. A., & Hurnik, J. F. (1996). The long-term productivity of hens housed in battery cages and an aviary. Poultry Science, 75(1), 47-51. Retrieved from Agricola doi: 10.3382/ps.0750047



  1. Your instructor is required to complete all the items in your cardex without any problems. Unfortunately, some instructors do not pay attention to the training rules and in 12 sessions, they only teach easy driving and detour and a simple dubbing park; If this happens to you, be sure to let the school know so that a new instructor can introduce you.

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