Molting in Chickens: Identification, Benefits, and Impact on Egg Production

Isaac Mugweru

Researcher

13 min read
15/01/2025
Molting in Chickens: Identification, Benefits, and Impact on Egg Production

Introduction

Molting in avian species is a natural process where birds shed old feathers and replace them with new ones (Mishra et al., 2022). This process is often associated with decreased reproductive function, leading to reduced egg production (Anwar et al., 2016). Molting can be either natural or induced (Zhang et al., 2022; Idris et al., 2024). Natural molting occurs periodically in a bird's life cycle, often coinciding with the end of a breeding cycle (Mishra et al., 2022). During this time, the hen's reproductive system rests (Sarıözkan et al., 2013). Induced molting, on the other hand, is a management tool used in commercial layer farms to trigger this process artificially (Chanaksorn et al., 2019; Khalf et al., 2023). It extends the productive life of laying hens by rejuvenating their reproductive organs, allowing for a second cycle of egg production (Khan et al., 2011; Khalf et al., 2023). This is typically done when a flock's egg production declines or the egg quality decreases (Ga et al., 2022; Idris et al., 2024). The induced method is not new, with the practice starting in the early 20th century (Anwar et al., 2016). While natural molting is a normal physiological event, induced molting is a management practice that artificially causes hens to shed feathers and cease egg production, often through methods that can be considered stressful (Chanaksorn et al., 2019; Ga et al., 2022). This process allows the hen to enter a non-reproductive state, which increases both egg production and egg quality post-molt (Khan et al., 2011). By inducing a controlled molt, farmers can manage the productivity of their flocks and minimize economic losses (Wang et al., 2023).

How to identify when your chickens are molting

Farmers sometimes mistake molting for mite infestation. One of the most common questions on this topic is how to distinguish between the two. Here are the key signs that indicate molting in layer chickens, helping to differentiate it from mite infestation:

  • Feather Loss: Molting is characterized by the shedding of old feathers, which is a natural and systematic process. This differs from mite infestations, where feather loss is often patchy and irregular, with signs of irritation. (Sarıözkan et al., 2013; Anwar et al., 2016; Mishra et al., 2022)
  • Reduced Egg Production: A significant drop in egg production is a primary sign of molting, as the reproductive system rests during this period. Hens may even completely stop laying eggs. While they can reduce egg production due to stress, mite infestations generally don't cause a complete cessation of laying. (Wang et al., 2023; Idris et al., 2024)
  • Changes in Body Weight: Molting is often associated with a noticeable decrease in body weight. The hens will lose weight as their bodies focus on feather regrowth. While birds with mite infestations may also lose weight due to stress, it is less drastic or consistent than molting. (Anwar et al., 2016; Idris et al., 2024)
  • Comb and Wattle Changes: During molting, the comb and wattle may appear smaller and paler, indicating a regression of the reproductive organs. Mites do not cause changes in the size and color of the comb and wattle; instead, they may cause redness and irritation in these areas. (Idris et al., 2024; Soomro, 2018)
  • Behavioral Changes: Birds undergoing a molt may become less active. They may also show reduced feed intake. Mite-infested chickens may exhibit restlessness, excessive preening, and pecking at their feathers, trying to relieve itching. (Koelkebeck & Anderson, 2007; Fard et al., 2020)
  • Feather Regrowth: After the old feathers are shed, new feathers will begin to grow. This is a key indicator of the recovery phase of molting. With mite infestations, feather regrowth may be stunted or abnormal, and the mites may damage new feathers. (Anwar et al., 2016; Zhang et al., 2022; Idris et al., 2024)
  • Physical Examination: A close inspection of the skin, particularly around the vent and under the wings, can help differentiate between molting and mite infestations. In molting, there should be no signs of skin irritation or small crawling parasites on the bird. Mite-infested birds, on the other hand, will show small mites or evidence of irritation, such as red or scaly patches on the skin. (Soomro, 2018; Idris et al., 2024)
  • Timing and Consistency: Molting generally occurs in a more predictable pattern across a flock, especially when induced, with hens showing similar signs around the same time. Mite infestations can spread through the flock but may not affect all birds simultaneously, and the signs are usually more varied in intensity between individual birds. (Idris et al., 2024)
  • Eye Ring Pigmentation: During molting, the pigmentation of the eye ring might be reduced. This sign is more specific to the molt and is not a symptom of a mite infestation. (Idris et al., 2024)
  • Vent Assessment: The vent of a hen during molt may appear dry and small. Mite infestations do not affect the condition of the vent. (Idris et al., 2024)

By observing these signs, farmers can accurately identify if hens are undergoing a molt or are suffering from a mite infestation, enabling them to implement the correct management and treatment protocols.

Benefits of Molting in Chickens

Most farmers may view molting as a negative occurrence with no production value. This is partially correct because, as much as it compromises the bird’s welfare, it is an important physiological process in layer production. Here are some of the benefits of molting in chickens.

  • Extended Production Life: Molting rejuvenates the reproductive system in hens, enabling them to produce eggs for a second cycle and thereby extending their productive life. This reduces the need for frequent flock replacements. (Khalf et al., 2023; Mishra et al., 2022)
  • Improved Egg Quality: Post-molt, hens tend to lay eggs with better shell quality, including increased shell thickness and strength, which is important for reducing breakage. Molting also improves internal egg quality, such as the albumen and yolk, enhancing their overall marketability. (Tiwary et al., 2019; Ga et al., 2022)
  • Increased Egg Production: A primary benefit of induced molting is restoring egg production to a profitable rate following the resting period. In many cases, post-molt egg production can reach levels comparable to or even higher than those of younger hens. (Anwar et al., 2016; Mishra et al., 2022; Idris et al., 2024)
  • Cost-Effectiveness: Moulting is a more economically viable option than replacing entire flocks. It allows farmers to continue production without the costs associated with purchasing new birds, making it a practical solution for maintaining profitability. (Mishra et al., 2022; Khalf et al., 2023)
  • Better Feed Conversion: Moulting can improve the feed conversion rate of hens, meaning they require less feed to produce the same amount of eggs, enhancing efficiency and reducing costs. (Khalf et al., 2023)
  • Disease Management: Molting can improve the bird's overall health and disease resistance post-molt and may help reduce the incidence of certain diseases. (Sandhu et al., 2007)
  • Enhanced Reproductive Health: Moulting results in the regression and rejuvenation of the reproductive organs. This allows for a more efficient production cycle after the molt, improving egg production, fertility, and hatchability. (Sarıözkan et al., 2013; Khalf et al., 2023; Idris et al., 2024)
  • Potential for Increased Fertility and Hatchability: In broiler breeders, induced molting can enhance fertility and hatchability, which are crucial for maintaining breeding stock. (Khalf et al., 2023)
  • Adaptability: Moulting provides the farmer with flexibility in managing production. It allows for a controlled non-laying period, which can be scheduled during times of low egg prices. (Idris et al., 2024)
  • Reduced Salmonella Colonisation: Some studies suggest that certain molting methods, particularly those involving specific diets, can help to reduce Salmonella colonization in hens. (Mishra et al., 2022; Wang et al., 2023)
  • Improved Bone Health: Moulting can aid in the improvement of bone mineral density, which is beneficial for the hen’s overall health and well-being. (Soomro, 2018)

By understanding and utilizing the benefits of molting, both farmers and researchers can optimize poultry production in a sustainable and economically sound manner.

Effects of molting on body characteristics and egg quality of layer chicken

Molting significantly impacts various aspects of a layer hen's physiology and productivity. A key effect is a marked reduction in body weight, often between 20% and 30% (Sarıözkan et al., 2013; Idris et al., 2024). This weight loss is a critical part of the molting process and is influenced by the specific method employed (Sarıözkan et al., 2013). Alongside body weight, there are also notable changes in organ characteristics, particularly within the reproductive system. The ovary and oviduct undergo regression, decreasing in weight and length as the hen's reproductive activity ceases during the molt (Rafeeq et al., 2013; Fard et al., 2020). This regression is essential for the subsequent rejuvenation of the reproductive system (Khalf et al., 2023).

A fundamental consequence of molting is the temporary cessation of egg production, which can occur at varying speeds depending on the molting method (Ga et al., 2022; Idris et al., 2024). Feed withdrawal methods typically result in a more rapid stop to egg-laying than non-feed withdrawal techniques (Ga et al., 2022). Following the resting period, however, egg production typically resumes, often reaching levels comparable to or exceeding pre-molt rates (Rafeeq et al., 2013; Khalf et al., 2023). The eggs' quality also improves, notably in eggshell strength and internal quality (Mishra et al., 2022). Post-moult, eggs often exhibit increased shell thickness and breaking strength, reducing the likelihood of cracked or broken eggs and hens may lay heavier eggs after a molt (Sarıözkan et al., 2013; Ga et al., 2022).

During the molt, feed intake is substantially reduced, corresponding with the reduced metabolic demands of a non-laying hen (Fard et al., 2020; Idris et al., 2024). Once the birds return to production, feed consumption typically returns to normal levels (Fard et al., 2020). Importantly, molting can improve the feed conversion ratio, allowing hens to produce more eggs with less feed, a crucial factor in economic efficiency (Mishra et al., 2022; Khalf et al., 2023). The molting method directly affects the hen’s overall health and mortality rate (Ga et al., 2022). Non-feed withdrawal methods tend to result in lower mortality than traditional feed withdrawal methods, which can induce significant stress (Ga et al., 2022; Mishra et al., 2022). Furthermore, specific molting methods can positively influence the immune response. Zinc supplementation, for instance, can lead to an enhanced humoral immune response, with increased production of key antibodies such as IgM and IgG (Sandhu et al., 2007).

Molting also induces various hormonal changes, with thyroid hormone levels fluctuating during this period (Soomro, 2018). Moreover, the gut microbiota may be disrupted during the molting process (Lei et al., 2023; Wang et al., 2023). However, using probiotics during non-feed withdrawal methods can help to maintain a stable and healthy gut microbial diversity (Wang et al., 2023). Finally, molting includes the natural shedding of old feathers and regrowth of new ones, which can contribute to an overall improvement in the bird's condition (Idris et al., 2024).

Understanding these effects is crucial for optimizing molting practices enhancing both productivity and welfare in layer chickens. By carefully managing the molting process, farmers and researchers can achieve significant improvements in egg production, quality, and overall flock health (Sandhu et al., 2007; Ga et al., 2022; Khalf et al., 2023).

How long should molting take, and how to know when the process extends into the post-molt production period?

The duration of the molting period varies depending on the method used but generally ranges from 4 to 6 weeks (Chanaksorn et al., 2019; Idris et al., 2024). Some non-feed removal methods may extend up to 28 days to achieve the desired body weight loss (Ga et al., 2022). Farmers must monitor their flock closely during this time. A successful molt is typically indicated by a body weight loss of 25-30% and a significant reduction or cessation of egg production (Khalf et al., 2023). Complete feed removal for 10 to 14 days combined with a reduced day length from 16 to 8 hours remains the best method for inducing a molt. A satisfactory level of molting can be determined when most of the plumage has fallen off (Idris et al., 2024).

The post-molt production phase begins as the birds start to regain weight and their reproductive systems rejuvenate (Khalf et al., 2023). Farmers should observe several key indicators:

  • Return to Egg Production: The most obvious sign of the post-molt phase is egg-laying resumption. This typically begins within a few weeks after the molting period and can be as early as 3 weeks in some cases. (Rafeeq et al., 2013)
  • Feather Regrowth: New feather growth is a good sign that the birds are recovering, and this should be monitored as it indicates a return to normal physiological function. (Zhang et al., 2022; Khalf et al., 2023)
  • Increased Feed Intake: As the hens transition into the laying phase, their feed intake will increase again. (Khalf et al., 2023)
  • Body Weight Gain: Following the initial weight loss, the birds should start to gain weight again. (Khalf et al., 2023)

If egg production does not resume within the expected timeframe or if the birds do not regain weight, it could indicate that the molting period has extended too long or that there are other underlying issues, such as health problems or poor management practices. This can lead to production losses (Idris et al., 2024). Monitoring feed intake, body weight changes, feather regrowth, and egg production is essential in managing this transition effectively and avoiding prolonged non-productive phases (Khalf et al., 2023).

Conclusion

Molting is a complex process crucial for rejuvenating laying hens, impacting body characteristics, production, and egg quality. Effective molting, whether through feed withdrawal or non-feed withdrawal methods, involves significant body weight loss and reproductive system regression, followed by a recovery phase characterized by renewed egg production and improved egg quality. Farmers should aim for a 25-30% body weight loss during the molt and monitor feather regrowth, feed intake, and egg production closely to identify the post-molt phase and avoid prolonged non-productive periods. Further research is needed to optimize non-feed withdrawal molting methods, such as using cassava meal, wheat bran, zinc oxide, or potassium iodide, to balance welfare concerns with productivity goals. Additionally, studies should focus on the influence of nutritional supplements, such as vitamins C and E, probiotics, and minerals, on the gut microbiota and overall health of molted hens. Investigating the genetic mechanisms and hormonal changes that underpin molting, particularly in the hypothalamus and ovaries, will also prove valuable in refining molting techniques.

References

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