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Written by Seven Kings
Have you ever wondered why eggs are so cheap compared to other proteins?
Humans have bred chickens that are super-able to lay eggs, of course, but strange breeding techniques have also allowed chickens to lay as many eggs as possible in a limited number of chicken births. Today we're going to introduce the story of egg laying that you don't know.
Image source: wikimedia
The first thing to point out is that the source of commercial layer chickens in the world is now very single. Bill Muir, a professor of animal science at Purdue University, said that although there are hundreds of chicken breeds in the world, there are only three breeds of commercial broilers and only one breed of layer chickens. Most of the world's layer chickens come from two companies: the American breeding company Hendrix and the German Roman Poultry Breeding GmbH (Lohmann).
Most of the commercial white layer chicken breeds belong to the White Leghorns. Image source: wikimedia
These laying hens are super egg-laying. In 2007, a report by the Food and Agriculture Organization of the United Nations (FAO) showed that from the beginning of the 20th century to the present, the egg-laying capacity of layer chickens has achieved a leap: 170 a year in 1925 and 325 in 2006.
However, even such a high-yielding breed cannot maintain a stable output throughout the chicken. Commercial layer chickens generally start laying eggs at 16-20 weeks of age, but egg production begins to decline around 25 weeks. By the time the hen is 72 weeks (18 months old), there is little commercial (egg laying) value.
So the chicken farm faces a difficult problem: do you want the old hens to continue laying eggs, or do you want to change a batch of tender chickens? Although young chickens have strong egg laying ability, they need to be updated by chicken farms for money.
After some weighing, humans came up with a middle way: to make old hens bald to give their fertility a second spring. This is the strategy widely used in the layer industry: induced molting.
Simply put, artificial forced moulting is a process of forcing poultry to shed their fur early by artificially simulating autumn.
Layer chickens undergoing artificial forced moulting. Image source: wikipedia
You may want to say that there is a relationship between hair change and laying eggs?
Feathers are very important to birds, so all birds change their feathers at least once a year. Because moulting is a very energy-intensive physiological response, and conflicts with reproduction and migration, birds generally change their hair after breeding, but not during migration.
A house swallow that is moulting. Image source: wikipedia
For hens, at the end of each natural egg-laying cycle, at the turn of summer and autumn, the hens will naturally moult, and the number and quality of eggs laid before moulting will decrease. And when the hen is moulting, the reproductive system will "shut down and restart". In general, high-yielding hens look miserable in the fall because they are particularly bald.
Gregg J. Cutler, former president of the American Association of Avian Pathologists, introduced that the physiology of birds and mammals is very different, during the egg laying period birds' livers will accumulate fat, and they will also grow a fat pad on their stomachs; during moulting, the fat of the liver and meat pads is consumed, and the ovaries are also absorbed and reused; after moulting, the chicken's reproductive system is replaced with old and new. Reproductive capacity is iterative. That is to say, moulting can be understood as the external manifestation of the hen's "confinement".
This natural phenomenon was once an important factor in the cyclicality of the egg industry. Because hens all shed their feathers in the autumn and do not lay eggs, before the advent of modern farming, the supply of eggs on the market in the autumn will decrease, and the price of eggs will increase.
But then humans found that they could reverse this natural law: forced hair removal allowed the hens to enter the next egg-laying cycle as soon as possible, so wouldn't they be able to make more money in the fall?
Morley A. Jull, a zoologist at the University of Maryland, documented the cultivation of forced moulting as early as 1938. Now many chicken farms will use forced moulting to make the old hens come again in order to save costs.
However, the specific measures of forced moulting have been criticized because this method looks very cruel.
In order to create artificial autumn, it is not enough to reduce the light. Farmers have found that in order for the hen's reproductive system to be restarted, the hen must lose about 30% of its body weight. Therefore, the chicken farm will starve the hens for 1-2 weeks and force them to shed their hair. After that, the chicken farm re-feeds the hens, and the hens can enter a new round of egg-laying cycles. In addition to layer chickens, the broiler, turkey and duck farming industries also use this strategy.
Although the method of forced moulting can extend the commercial life of the hen, it cannot be used indefinitely, because every time the hair is lost, the egg production cycle of the hen can be restarted, but the egg production will also be discounted, usually 7-8% off the previous cycle. Therefore, more than 2 years old can be regarded as an old hen with no economic value (although 2 years old is far less than their natural lifespan - 5-10 years).
Old hens, which no longer have egg laying value, are called spent hens in the industry, and they are usually pulled to slaughter and made into low-grade chicken products.
Eliminate the dried chicken made from layer chicken. Image source: (DOI) 10.5851/kosfa.2016.36.3.326
For many consumers, forced moulting is too brutal, so big restaurant chains such as Golden Arch, Burger King and Wendy Burger claim not to use artificial forced moulting of eggs. The United Kingdom banned forced moulting in 1987 and the European Union banned this farming law in 1988. Of course, layer chickens in these countries are directly destroyed or "recycled" directly after the peak egg-laying period is over.
At the same time, researchers and the layer industry are also developing new methods of artificial forced moulting. Another common method of forced moulting now is called the chemical method, which does not deliberately diet the hens, but makes them hair-dropping through high-zinc feed.
However, some layer chicken farms in the United States still use manual forced moulting. According to a survey conducted by the U.S. Department of Agriculture in 1999, 74 percent of farms in the U.S. at the time forced hens to moult.
In 2008, the United Egg Producers no longer allowed its egg farmers to use starvation to force moulting of laying hens. More than 80 percent of eggs in the United States are produced under the regulations of the United Egg Farmers Association, and farmers who do not join the United Egg Farmers Association can still moult the hens by depriving them of food.
Artificial forced moulting is also available in some layer farms on the mainland. According to a 2017 report released by the U.S. Department of Agriculture, China's poultry industry extended the service life of laying hens through manual forced moulting from 2016 to 2017.
USDA: China's poultry industry extended the life of layer chickens through manual forced moulting in 2016-2017. Screenshot source: www.fas.usda.gov/data/china-poultry-and-products-annual-2
During the COVID-19 pandemic, forced moulting has also reduced losses for mainland farmers. In March 2020, Xinhua Daily Telegraph reported that because the epidemic affected logistics, feed could not be transported to chicken farms, and many layer chicken farmers were forced to implement mandatory moulting of layer chickens, so that they entered a similar temporary "dormant" state, thus avoiding death while saving feed.
Some scholars believe that forced moulting is no more cruel to birds than nature itself, because many birds experience natural feeding and hunger strike cycles in nature. For example, in the natural environment, geese can go on hunger strike for two and a half months, and king penguins (Aptenodytes patagonicus) can go on hunger strike for 4-6 months.
King penguins (Aptenodytes patagonicus) can starve for more than half a year. Image source: wikimedia
Whether it is more "part-time work" for a year to be exploited by surplus value, or to be eliminated early after the peak, the problem seems to be temporarily unsolvable.
Bald chickens have eggs for making hair.
Cover source: pixabay
Resources:
https://docs.qq.com/doc/DVHlnQkVWQ2ZSeFRp
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