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Chicken Psychology: Catering to Complex Relationships within Cage-Free Flocks

July 8, 2024
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With the continued transition from conventional, caged layer farms towards alternative egg production systems, veterinarians, researchers, and farmers have been heavily scrutinizing the behavioral needs of chickens in their new group-housed environments.

Historically, poultry farms optimized the ability of laying hens to be efficient and prolific egg layers in multi-level battery cages – where a hen would share her small environment with a few “roommates” for the entirety of her laying cycle. However, various political, societal, and technological pressures have fueled a significant shift in the U.S. laying hen industry towards cage-free egg farming. Phasing out of fad territory, this shift is here to stay and expected to expand.

And unfortunately, it’s not as simple as just erecting an aviary, filling it with birds, and then counting your eggs. Conversely, caretakers must systematically re-work their entire husbandry and health programs in order to have a chance at being successful. It is paramount that a holistic approach is thoroughly researched ahead of time on how to best support the mental and physical needs of the commercial laying hen BEFORE she is placed into a “jungle gym” with thousands of other flock mates. What I’ve seen over the last 10 years is that those who collaborated with industry colleagues, got an early start on their transition process, and thoroughly trained their staff ahead of time have fared far better during the cage-free learning curve compared to their peers.

Colloquially, “cage-free” is used by many consumers as a catch-all phrase that encompasses the spectrum of alternative production systems that don’t use conventional cages. Yet, within the industry itself, there are vastly different systems in which to house cage-free birds. Simply put, the most popular alternative production classes are as follows:

  • Cage-free – group housed flocks in an indoor, climate-controlled barn
  • Free-range – group housed flocks with access to the outdoors
  • Pasture-Raised – group housed flocks with access to a lot of the outdoors
  • Organic – group housed flocks with access to the outdoors and in compliance with the USDA’s National Organic Program concerning organic feed, supplements, and medications

The dynamics of group housed laying hens are extraordinarily different and comparatively more complex than those required of caged birds. Mathematically speaking, a single hen now has the ability to interact with an exponentially larger number of conspecifics on a daily basis. While obviously more mentally stimulating than living next to her same five roommates for her entire laying cycle, this can exacerbate some undesirable tendencies. Specifically related to bird behavior, some flocks can experience excessive pecking, cannibalism, piling, mislaid eggs, and feather pulling – and if not proactively accounted for, these issues are far more difficult to correct than they are to prevent.

Concerning pecking, cannibalism, and feather pulling, a multi-system approach must be considered when identifying potential root causes and corrective actions. This can include investigations into lighting, stocking density, and nutrition. Seeing as chickens perceive light through the tops of their heads in addition to their eyes, excessively high light intensity can result in irritation and aggression. Light dimming technologies are useful in these instances as long as the dimming doesn’t result in light flicker. Additionally, excessively high stocking densities can cause intense competition surrounding resource access to feed troughs, water nipples, and nest boxes. And regarding nutrition, deficiencies in methionine and insoluble fiber can leave the birds unsatiated to the point that they violently seek out each other’s tail and back feathers. Early identification of intra-flock aggression is valuable, as there are a large number of potential flock mates that can “gang up” on submissive hens in group housing systems.

Concerning mislaid eggs, this unique issue to cage-free egg farming can be mitigated with an emphasis on pullet training and environmental management. As young birds, the ability to consistently ascend and descend the aviary tiers must be taught and encouraged through lighting, system design, and human intervention if necessary. It should come as no surprise that an untrained pullet will not be a consistent nest layer and will have to have her eggs hand-picked off the ground and placed onto the egg belt. Additionally, excessively dark floors with high litter depths can actually encourage birds to spend too much time on the ground as opposed to their nest boxes. The best nest boxes are abundantly available, dark, and provide visual barriers from the general population.

Concerning piling, great care should be taken when walking in a cage-free barn so as to not startle the birds into a state of stampede. This is accomplished by desensitizing the pullets to human noise and movement during the rearing phase and by proper, supervised training of new employees during the onboarding process.

And while the commercial poultry industry’s story of continually improving the bird’s experience will inevitably be that of a journey as opposed to a destination, I find it heartening to have witnessed first-hand the tangible progress being made year over year. It is wildly fulfilling to re-visit historically problematic farms only to observe thousands of calm, healthy birds exhibiting normal behaviors and going about their daily business in a peaceful manner. This allows me to remain optimistic that one day we’ll be able to consistently achieve the same flock production metrics in cage-free aviaries as we’ve done in conventional, caged systems – or better.

Alexander W. Strauch, DVM, MBA