Forced molting
Encyclopedia
Induced molting is the practice by the commercial egg
industry of artificially provoking a complete flock of hens
to molt simultaneously. During the molting period, the hens go out of production for a period of at least two weeks. This has the effect of allowing the hen's reproductive tracts to regress and rejuvenate. After a molt, the hen's production rate usually peaks slightly below the previous peak rate and egg quality is improved. The point of molting is thus to increase the production, egg quality, and profitability of flocks in their second or third laying seasons. Flocks that are slaughtered after a single laying season are not molted.
Molting simulates the natural process where chicken
s grow a new set of feather
s in the fall, a process generally accompanied by a sharp reduction or cessation of egg production. Natural molting is stimulated by shortening day lengths combined with stress (of any kind). Before confinement housing with artificial lights were the norm, the fall molt caused a fall scarcity of eggs and high market prices. Farmers attempted to pamper their flocks to prevent the molt as long as possible, to take advantage of the high prices. Modern controlled-environment confinement housing has the opposite problem; the hens are not normally presented with sufficient stress or cues to go into molt on their own. However, after laying continuously for nearly a year, their rate of egg production declines, as does the quality of the eggshell
and the egg contents. In addition, the hens are seriously overweight.
For a complete recovery of the reproductive tract the hen's body weight must drop 30 to 35 percent during the molt. This is achieved by withdrawing the hen's feed for 7-14 days or up to 28 days under experimental conditions which presumably reflect standard farming practice in some countries. This means the hens lose their feathers and cease to lay eggs in addition to losing weight. Some die during this period. North and Bell insist that the flock must be managed so that mortality does not exceed 1.25% over the 1–2 weeks of nearly complete feed withdrawal, compared to a 0.5% to 1.0% monthly mortality in a well-managed flock under low-stress conditions. In 2003, more than 75% of all flocks were moulted in the US.
Molting programs follow many variations. Some do not eliminate feed altogether but may induce a moult by providing a low-density diet (e.g. grape pomace, cotton seed meal, alfalfa
meal) or dietary manipulation to create an imbalance of a particular nutrient(s). The most important among these include manipulation of minerals including sodium
(Na), calcium
(Ca), iodine
(I) and zinc
(Zn), with full or partially reduced dietary intakes. Some programs combine feed withdrawal with a short period of water withdrawal. Most programs also restrict the amount of lighting to provide a daylight period that is too short to stimulate egg production, providing a simulated autumn, the natural time of molt and minimum egg production.
Forced molting is not a common practice in Canada, where the animal welfare issues associated with it has rendered it basically obsolete.
It is sometimes claimed that forced molting is an artifact of factory farming, but, like virtually all poultry practices, it predates the vertical integration
of the poultry industry by decades. Jull prescribes a precise molting program in his 1938 book, Poultry
Husbandry.
Egg (food)
Eggs are laid by females of many different species, including birds, reptiles, amphibians, and fish, and have probably been eaten by mankind for millennia. Bird and reptile eggs consist of a protective eggshell, albumen , and vitellus , contained within various thin membranes...
industry of artificially provoking a complete flock of hens
Chicken
The chicken is a domesticated fowl, a subspecies of the Red Junglefowl. As one of the most common and widespread domestic animals, and with a population of more than 24 billion in 2003, there are more chickens in the world than any other species of bird...
to molt simultaneously. During the molting period, the hens go out of production for a period of at least two weeks. This has the effect of allowing the hen's reproductive tracts to regress and rejuvenate. After a molt, the hen's production rate usually peaks slightly below the previous peak rate and egg quality is improved. The point of molting is thus to increase the production, egg quality, and profitability of flocks in their second or third laying seasons. Flocks that are slaughtered after a single laying season are not molted.
Molting simulates the natural process where chicken
Chicken
The chicken is a domesticated fowl, a subspecies of the Red Junglefowl. As one of the most common and widespread domestic animals, and with a population of more than 24 billion in 2003, there are more chickens in the world than any other species of bird...
s grow a new set of feather
Feather
Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...
s in the fall, a process generally accompanied by a sharp reduction or cessation of egg production. Natural molting is stimulated by shortening day lengths combined with stress (of any kind). Before confinement housing with artificial lights were the norm, the fall molt caused a fall scarcity of eggs and high market prices. Farmers attempted to pamper their flocks to prevent the molt as long as possible, to take advantage of the high prices. Modern controlled-environment confinement housing has the opposite problem; the hens are not normally presented with sufficient stress or cues to go into molt on their own. However, after laying continuously for nearly a year, their rate of egg production declines, as does the quality of the eggshell
Eggshell
An eggshell is the outer covering of a hard-shelled egg and of some forms of eggs with soft outer coats.- Insect eggs :Insects and other arthropods lay a variety of styles and shapes of eggs. Some have gelatinous or skin-like coverings, others have hard eggshells. Softer shells are mostly protein....
and the egg contents. In addition, the hens are seriously overweight.
For a complete recovery of the reproductive tract the hen's body weight must drop 30 to 35 percent during the molt. This is achieved by withdrawing the hen's feed for 7-14 days or up to 28 days under experimental conditions which presumably reflect standard farming practice in some countries. This means the hens lose their feathers and cease to lay eggs in addition to losing weight. Some die during this period. North and Bell insist that the flock must be managed so that mortality does not exceed 1.25% over the 1–2 weeks of nearly complete feed withdrawal, compared to a 0.5% to 1.0% monthly mortality in a well-managed flock under low-stress conditions. In 2003, more than 75% of all flocks were moulted in the US.
Molting programs follow many variations. Some do not eliminate feed altogether but may induce a moult by providing a low-density diet (e.g. grape pomace, cotton seed meal, alfalfa
Alfalfa
Alfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...
meal) or dietary manipulation to create an imbalance of a particular nutrient(s). The most important among these include manipulation of minerals including sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
(Na), calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
(Ca), iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
(I) and zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
(Zn), with full or partially reduced dietary intakes. Some programs combine feed withdrawal with a short period of water withdrawal. Most programs also restrict the amount of lighting to provide a daylight period that is too short to stimulate egg production, providing a simulated autumn, the natural time of molt and minimum egg production.
Forced molting is not a common practice in Canada, where the animal welfare issues associated with it has rendered it basically obsolete.
Criticism
This temporary starving of the hens is seen as inhumane and is the main point of objection by critics and opponents of the practice. The alternative most often employed is to slaughter the hens instead of molting them.It is sometimes claimed that forced molting is an artifact of factory farming, but, like virtually all poultry practices, it predates the vertical integration
Vertical integration
In microeconomics and management, the term vertical integration describes a style of management control. Vertically integrated companies in a supply chain are united through a common owner. Usually each member of the supply chain produces a different product or service, and the products combine to...
of the poultry industry by decades. Jull prescribes a precise molting program in his 1938 book, Poultry
Poultry
Poultry are domesticated birds kept by humans for the purpose of producing eggs, meat, and/or feathers. These most typically are members of the superorder Galloanserae , especially the order Galliformes and the family Anatidae , commonly known as "waterfowl"...
Husbandry.
External links
- The Animal Welfare and Food Safety Issues Associated With the Forced Molting of Laying Birds (United Poultry Concerns)
- Induced Molting as a Management Tool (North Carolina State University)
- Induced Molting of Commercial Layers (North Carolina State University)
- Forced Molting of Laying Birds (Poultry.org)