- Chickens are being raised to have smaller bodies but they lay bigger eggs and more of them
- Producing 10 times the normal number of eggs leads to calcium deficiency, causing bones to become brittle
- The stress of trying to hatch a very large egg is breaking their keel bone, which connects their torso and wings
- fractures, which occur in both caged and cage-free birds, and are painful for weeks
- Scientists suggest that farmers delay laying eggs until the hen is mature and her keel bone is completely hardened
Modern egg-farming practices are sabotaging chickens’ bodies, according to a new study from Denmark.
Forced to lay 10 times more eggs than their normal number, farm hens quickly lose calcium and develop brittle bones and fractures and may become egg-bound, or unable to hatch their eggs.
According to a new report from the University of Copenhagen, about 85 percent of Danish chickens are suffering a fracture in their keel bone, a major bone that attaches to their bodies, due to the pressure of trying to push eggs too large for their bodies. exits. Tits and connects their torso and wing muscles.
“We knew there was a problem, but we certainly didn’t expect it to apply to nearly all laying hens in the country,” said lead author Ida Thofner, from the university’s Department of Veterinary Medicine and Animal Sciences.
Unlike humans with a fractured bone, birds are not given the option of casts, medication, and bed rest.
‘When a fracture happens and later these animals suffer, we are dealing with a huge animal welfare problem here.’
The problem is globally endemic, Thofner said.
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The nail bones shown below in Figures A and B are broken, while the right in Figures C and D are not fractured.
Chickens in the industrialized world are raised to produce larger eggs and more of them: in the wild, a hen lays about 20 eggs a year, but on a modern farm she 275. dropped around within the same time frame.
Thofner and Jens Peter Christensen, professors of veterinary clinical microbiology, examined about 4,800 chickens in 40 different herds for keel bone fractures and found about 4,100 of them.
While advocates of animal-welfare often encourage organic and cage-free chickens to be raised, Christensen said the fractures were ‘obvious across all production systems …
‘In other words, this is a widespread problem in all parts of the industry,’ he said.
In a study published this month Journal PLOS OneThe nature of the breaks, which usually occur at the tip of the keel bone, indicates that they are due to the birds being under too much stress trying to pass these giant eggs, the researchers reported.
The keel (above) is the major bone that protrudes from a chicken breast and attaches to their torso and wing muscles.
Researchers in Denmark found that 85 percent of egg-laying chickens had fractured keel bones because their bodies were too small to push out the large eggs they were born to lay.
“The bigger the eggs and the smaller the chickens, the bigger the problem,” Christensen said. Unfortunately, chickens are ‘bred to be small and to lay too many large eggs.’
Undoing that genetic modification can take generations of poultry breeding, Christensen said.
According to a 2018 article Frontiers in Veterinary ScienceUntil the hen is about 40 weeks old, the keel bone continues to grow and harden.
But most chickens are put into egg production at 16 weeks, when several centimeters of the tip of the keel bone remain ‘fully cartilaginous’.
That 2018 study by researchers from the University of Aarhus and the University of Guelph found evidence to ‘strongly suggest that fractures are a source of pain, at least for weeks after the event.’
But Christensen and Thofner say there is an easier solution that benefits both birds and farmers.
By postponing the egg laying for a few weeks, the hens become mature and their pelvis hardens completely.
Modern chicken lay eggs have been bred for generations to have smaller bodies but produce larger eggs. The result is a calcium deficiency that can lead to brittle bones and fractures and can cause eggs to bind, when the hen cannot pass her eggs.
95 percent of egg-laying chickens in the US are kept in barren battery cages, which are housed in a single shed for tens of thousands of birds.
It’s a cost-effective strategy, Thofner said, ‘because hens only lay eggs for a longer period of time.’
But turning its way from egg farmers is no minor feat: The US egg industry alone is worth nearly $10.6 billion, according to statista, where Americans eat an average of 288 eggs a year.
and keel bone fractures are hardly the only problem—according to compassion in world farming, 95 percent of chickens that lay eggs in the US are kept in barren battery cages, which were outlawed in the European Union in 2012.
only about 30 percent Of the 111.6 billion eggs produced in the US in 2020, they were organic or cage-free.
Each of these cages holds up to 10 birds, with an individual chicken having less floor space than a sheet of paper and enough height to stand on.
The cages are placed in tiers and a single shed can house thousands of hens. (The largest one has over a million.)
These huge piles are difficult to observe so often injured, diseased and even dead birds go unnoticed. Salmonella has been found to be more prevalent in barren battery cage systems.
Chickens never enjoy fresh air or sunlight until they are taken out for slaughter and, to prevent them from pecking each other, part of their beaks—their primary sensory organ—when they If there are chicks, they are cut with a blade or infrared light.