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Rotten Eggs

egg illustrationA recent press release issued by the Humane Society of the United States (HSUS) and United Egg Producers (UEP) may have caught your eye. The press release heralds an “historic” new agreement on future egg production between HSUS and UEP, an industry body which represents 80% of all U.S. egg producers. A strange union, you might think, for two organizations normally at odds. So what exactly is this agreement about?

In his blog, HSUS president Wayne Pacelle says that the “landmark agreement” will “help millions of hens.” HSUS has been calling for cage-free egg production for years, so an agreement to end all caged egg production would represent an enormous advancement in welfare. Sadly for the hens, that isn’t the basis of this agreement.  In defiance of common sense, and all previously expressed opinion, HSUS has achieved nothing more than an agreement to work with UEP towards new legislation which will move hens out of one type of battery cage into a another slightly larger cage. An historic welfare advancement? I think not.

HSUS claims that this new cage isn’t the same as the standard battery cage; it’s an “enriched” cage. So what exactly is an “enriched” cage and what welfare benefits does it offer the hens? HSUS claims that the “enriched” cages will provide environmental enrichments so birds can engage in important natural behaviors, such as perching, using nest boxes, and having scratching areas. But can a bird that is still behaviorally very much like its ancestor the jungle fowl really express natural behavior in a cage?

The answer is a definitive “no.” The word “enrichment” has positive connotations that quite frankly are not supported by science. In a previous blog, I state that these cages are better described as “furnished” rather than “enriched.” This may seem like wordplay, but the point is that while adding a perch or a nest area to a cage can be factually described as furnishing it, it’s a matter of (scientific) opinion as to whether or not it actually “enriches” the confinement of the bird. Let me explain.

The provision of perches is one of the claimed welfare benefits of furnished cages. Now, you might wonder how it is possible for a bird to get up on a perch in a cage. I suspect that your picture of a bird roosting is probably similar to mine: a bird in a tree or in the rafters of a barn, high up to enable the bird to feel safe from predators and other threats. In a furnished cage the perch is likely to be less than 3 inches off the floor, while the wire top of the cage will be just 15 inches above that. You might argue that as no predators can get into cages the bird must automatically feel safe, but this misses the point. Chickens originate from jungle fowl of southern Asia and, regardless of the cross breeding and hybridization of the species over the years, their natural behavior remains pretty much the same. Scientists have established that in order for chickens to be free from fear and distress they need to be able to get up on a perch where they feel “safe” (Olssen and Keeling 2000; Cooper and Albentosa 2003).

Scientists in Europe have already established that the furnished cage “perch” just isn’t up to the job. In 2012, standard battery cages will be prohibited across the whole of the European Union, following the introduction of legislation in 1999. To assist farmers in the transition, the European Union has funded a huge amount of research into furnished cages and bird welfare. The EU Animal Health and Welfare Panel (AHAW, 2005a) states that “Resting and perching are important aspects of birds’ welfare. Roosting at night on an elevated perch is a behavioral priority.” At just a couple of inches off the floor, scientists have established that hens will regard the “perch” in a furnished cage simply as part of the floor and not as a perch (Tauson, 1984).

Let’s move on to another of the other supposed benefits of a furnished cage: the fact it has a nest area. It is well established that hens place a high value on a secluded nest site. Research has shown that hens will move weighted doors and squeeze through gaps to get to what they consider to be a suitable site. Early work on enriched cages (Guesdon and Faure, 2004) showed that eggs laid in the nest area varied between 43% and 68% in a trial comparing four designs of furnished cages with standard cages. This suggests that the nest areas were not always satisfactory for the hens and reiterates the “furnished versus enriched” argument. The provision of a nest site is not the point: the hens must find it acceptable or they won’t see it as “enrichment.”

The reduced space in cages generally, combined with the small area set aside for nesting in furnished cages, is also a problem. Hens naturally lay at the same time each day – early in the morning – so there could be a line of hens waiting for their turn to get into the nest area. This is not an issue for non-cage systems which provide far more space and more numerous nest boxes.

In some reports on the recent agreement HSUS is quoted as saying that these new cages are better because they are 12 foot by four foot (or 48 square feet). Again, this really is missing the point: the actual size of the cage is nowhere near as relevant as the amount of space each bird gets. A standard broiler house will be around 20,000 square feet, but each of the 20,000 or more birds within the house only gets about 1 foot square as its personal space allowance. Let’s be very clear that whether the cage is 20 inches by 21 inches like a standard battery cage, or 12 foot by four foot, we are still talking about confinement of chickens in cages.

So what exactly is the benefit for the individual bird when moving from a standard to an “enriched” cage? The UEP press release says that as part of its agreement with HSUS the two groups will jointly ask Congress for federal legislation which would require egg producers to increase space per bird in a “tiered phase in,” with the amount of space birds are given increasing, in intervals, over the next 15-18 years. Currently, the majority of birds are each provided 67 square inches of space. The proposed phase-in would culminate with hens eventually being provided with 124-144 square inches of space.

Leaving aside the fact that it sounds like (at least initially) farmers could install enriched cages and still stock them at the same rate as they currently stock their standard battery cages, we need to ask if 144 square inches per bird is sufficient space? On one hand you might say that any increase in space must be positive for the birds; but on the other, if those in the egg industry are going to claim great changes to their systems then they ought to be meaningful. Of course, it’s natural to think that if a hen is moved from 68 square inches to 144 square inches she will feel like she’s gained something. But unfortunately that isn’t how it works: A hen put in a cage that allows her 144 square inches doesn’t know how lucky she is to have more than 68 square inches room. She simply finds that she hasn’t got enough room to move. Her individual welfare is not improved.

Dawkins and Hardie (1989) looked at the average space required by a hen to carry out basic needs and found that a bird requires an average space of 198 square inches to turn; stretching wings requires 138 square inches; and flapping wings 290 square inches. You’ll probably notice that these figures are all far greater than the space provided per bird in a furnished cage. Of course, each cage holds more than one hen and will be greater than 144 square inches in total, so you could argue that within the cage there is 290 square inches for a particular hen to flap her wings at any given time. Of course, she’d have to count on the co-operation of all the other hens to move out of her way and not want to stretch their own wings at the same time as her. And we’re not even considering the need of the bird to run, fly and forage.

Dustbathing is another key natural behavior (Lindberg and Nicol, 1997) that the furnished cage is supposed to facilitate. Dustbathing involves the hen lying down and throwing litter or other loose material over the feathers of their backs and wings; rubbing it in and then shaking it out. When hens do not have a suitable area and litter in which to dustbathe, they still go through the motions of dustbathing. This is known as sham ‘dustbathing’ and research suggests that it does not properly satisfy the motivation of hens to dustbathe. Scientists found that in enriched cages sham dustbathing on the wire cage floor takes place far more frequently than in the littered area (Lindberg and Nicol, 1997), with two thirds of dustbathing taking place outside of the designated area. At first it was thought that the restricted space in cages was contributing to this and that as dustbathing tends to take place at the same time each day (like egg laying) the birds would be motivated to dustbathe at the same time. But further research (Olsson and Keeling, 2002) shows that there was no relation between sham dustbathing and competition for use of the litter area. This suggests that the area, the type of litter provided, and the depth of litter provided in furnished cages just does not meet the hens’ requirement for a dustbathing area. Like the nest box, it’s not just the provision of a designated area that is important; it’s whether the hens see it as acceptable. In non-cage systems where there is litter on the floor and/or access to outdoor areas there is no evidence of sham dustbathing (AHAW, 2005b). Remember, too, that this agreement between UEP and HSUS does absolutely nothing to address other important welfare issues, such as routine removal of part of the birds’ beaks in caged egg production systems to prevent them from pecking each other in the confined conditions.

Of course, this agreement between HSUS and UEP will ultimately mean very little if the proposed legislation is not actually passed or becomes watered-down during its journey through Congress. Call me a cynic but to assume that the poultry lobby won’t attempt to influence the legislative process is somewhat naïve. In light of this newfound concern for animal welfare, I am also intrigued to know what plans UEP now has to amend its own standards. Or maybe UEP is just happy to wait for the legislation – if and when it comes…

But perhaps the most perplexing aspect of this recent agreement is that just over a year ago HSUS carried out a review of the welfare problems associated with enriched cages, which concluded that enriched cages provided “an unacceptably limited amount of space per bird.” Having reviewed the science myself I am at a complete loss as to what changes have occurred in the last year to make these previously unacceptable enriched cages suddenly so acceptable to HSUS. And while we can debate whether there is any welfare benefit to the agreement reached between UEP and HSUS, it is frankly unacceptable for Wayne Pacelle and HSUS to now present enriched caged systems as “humane.” The fact is that this new agreement between HSUS and UEP appears to offer little in terms of animal welfare, yet much in terms of positive PR. In light of these concerns, perhaps the two parties involved would agree to publicize the full terms of the agreement to allow an open, honest and democratic debate. Until that point I have to assume there are other forces at play, because I fail to see how this private backroom agreement that effectively leaves billions of hens in cages achieves much at all.


AHAW (2005a) Opinion of the Scientific Panel on Animal Health and Welfare on a request from the Commission related to welfare aspects of various systems of keeping laying hens (Question EFSA-Q-2003-092), adopted by the AHAW Panel on 10th and 11th November 2004. The EFSA Journal, 197: 1-23.

AHAW (2005b) Report of the Scientific Panel on Animal Health and Welfare on a request from the Commission related to welfare aspects of various systems of keeping laying hens (Question EFSA-Q-2003-092), accepted by the AHAW Panel on 14th and 15th September 2004. Annex to The EFSA Journal, 197: 1-23.

Cooper, J. J. and Albentosa, M. J. (2003) Behavioural priorities of laying hens. Avian and Poultry Biology Reviews, 14: 127-149.

Dawkins, M. S. and Hardie, S. (1989) Space needs of laying hens. British Poultry Science, 30: 413-416.

Guedson, V. and Faure, J. M. (2004) Laying performance and egg quality in hens kept in standard or furnished cages. Animal Research, 53: 45-57.

Lindberg, A. C. and Nicol, C. J. (1997) Dust-bathing in modified battery cages: Is sham dust-bathing an adequate substitute? Applied Animal Behaviour Science, 55: 113-128.

Olsson, I. A. S. and Keeling, L. J. (2000) Night-time roosting in laying hens and the effect of thwarting access to perches. Applied Animal Behaviour Science, 68: 243-256.

Olsson, I. A. S. and Keeling, L. J. (2002) No effect of social competition on sham dustbathing in furnished cages for laying hens. Acta Agriculturae Scandinavica, Section A, Animal Science, 52: 253-256.

Tauson, R. (1984) Effect of a perch in conventional cages for laying hens. Acta Agriculturae Scandinavica, 74: 193-209.

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