As winter approaches, the climate gradually becomes dry and cold, the difference between daytime and nighttime temperatures increases, and sunlight is insufficient. Laying hens often experience a decline in egg production due to cold stress. Cold temperatures also directly lower the flock’s resistance, creating favorable conditions for disease outbreaks and transmission. Winter is therefore a peak season for viral diseases in laying hens. Strengthening disease prevention and control for laying hens in winter is an important way to ensure that they maintain high and stable production in autumn and winter and that the flock grows healthily.
一、Common diseases in laying hens in autumn and winter
Common winter diseases in laying hens mainly include viral diseases, bacterial diseases, nutritional diseases, and stress syndromes.
Viral diseases mainly include “avian influenza, viral cold, infectious bronchitis in chickens, infectious laryngotracheitis in chickens, and egg drop syndrome”; bacterial diseases mainly include “colibacillosis, fowl cholera, salmonellosis in chickens, infectious coryza in chickens, and staphylococcosis in chickens”; nutritional diseases mainly include deficiencies in trace nutrients (vitamins and mineral elements). Fatty liver and gout in laying hens are specific manifestations of disorders of animal nutritional metabolism. The most common stress syndrome occurs when temperatures drop sharply during seasonal transitions, such as from summer to autumn or autumn to winter, causing cold stress syndrome in laying hens. Cold stress in laying hens can reduce immunity and egg production, and can also readily lead to secondary (concurrent) conditions.
二、Prevention measures for various diseases
1, Viral diseases
The main viral disease commonly affecting laying hens is avian influenza. This disease is highly harmful, and its outbreaks and spread often cause major economic losses to the poultry industry. It is currently an important factor affecting the healthy development of the poultry industry. Strengthening husbandry management and maintaining routine sanitation and disinfection are important measures for effectively preventing the disease. Establish and maintain a standardized sanitation and disinfection system, and cut off disease transmission routes as far as possible. Confine and isolate affected laying hens for treatment and disinfection, and safely dispose of carcasses of dead laying hens in accordance with established procedures. Bury contaminated materials and litter deeply or incinerate them.
Vaccinate according to the actual circumstances and strictly follow the relevant immunization program to greatly reduce the likelihood of disease outbreaks. In daily management, provide the flock with a suitable environment for growth. In winter, ensure adequate heating and ventilation, reduce adverse stress caused by drafts, and provide high-quality feed to meet the nutritional needs of laying hens.
Mild influenza H9 occurs throughout the year, especially commonly in autumn, winter, and spring. Incidence is lower in summer, but mild influenza H9 consistently has the highest incidence among poultry diseases. Some individual chickens in a flock show respiratory symptoms such as “rattling” and coughing. Respiratory symptoms in most chickens are difficult to hear during the day, but “rattling” can be heard after the lights are turned off at night; the disease spreads rapidly through the respiratory tract. Some individual chickens may also make unusual calls, while a small number show lethargy, facial swelling, green droppings, or diarrhea; some eggs may have sandpaper shells, cracked shells, or soft shells. This disease is largely affected by environmental factors. Maintaining a stable environment, controlling ventilation, improving the birds’ condition, and reducing stress are fundamental to preventing its occurrence.
2, Bacterial diseases
Bacterial diseases mainly include Escherichia coli disease in chickens. This is currently one of the important diseases affecting laying-hen production. These diseases are mainly secondary infections and can cause serious harm, resulting in lower egg production rates, lower feed returns, and higher laying-hen culling rates, thereby reducing laying-hen productivity and having a serious impact.
Strengthening husbandry management and environmental hygiene, especially feed and drinking-water hygiene, is an important measure for effectively preventing outbreaks of these diseases. At the same time, pay attention to ventilation and heating in the poultry house to avoid excessive ammonia levels, which can trigger respiratory diseases. Adding preventive medication to the feed can reduce the likelihood of outbreaks of these diseases. Prompt treatment is an important measure for effectively preventing and controlling these diseases. Follow the principle of early detection and early treatment: promptly confirm the disease based on clinical symptoms, laboratory diagnosis, and other methods, and develop an effective treatment plan to reduce the economic losses caused by these diseases.
3, Nutritional diseases
Key to preventing and treating nutritional diseases in laying hens is scientifically formulating and feeding a complete diet. When formulating feed for laying hens, carefully refer to national standards and ensure an appropriate balance of key nutrients, including crude protein, energy sources, dietary fiber, and trace elements (minerals and vitamins), to fully meet the normal nutritional needs of laying hens for growth, development, and egg production.
Long-term deficiencies or excesses of key nutrients can cause illness in laying hens and reduce egg production and egg quality. Therefore, during periods of sharp temperature drops, it may be necessary to appropriately increase the inclusion rate and feeding amount of certain nutrients. However, carefully control the feed amount. Ideally, maintain body condition at around 9成 to help laying hens achieve optimal production performance (egg-laying performance). Excessive feeding can easily lead to substantial fat deposition and may instead reduce egg production; in severe cases, it may also cause fatty liver or gout.
4, stress syndrome
A common adverse stressor facing laying hens in winter is temperature fluctuation (cold stress). When the short-term temperature fluctuation inside a layer house is 5°C–7°C and the lower temperature limit is below 13°C, laying hens experience obvious discomfort and are prone to developing various disorders. The temperature range to which domestic laying hens adapt is 13°C–20°C. Feed efficiency and egg production are best at around 18°C. If the temperature falls below 13°C, feed consumption increases while egg production declines, so the temperature and humidity inside the house must be carefully controlled.
In addition, environmental pollution, cold and damp conditions, noise and fright, arbitrary relocation and mixing of flocks, overcrowding, frequent feed changes, water shortages (drinking water), and indiscriminate use of drugs (antibiotics) are all common adverse stressors. Eliminating these stressors is an important measure for reducing the incidence of disease in laying hens.
Changes in indoor and outdoor conditions brought about by winter usher in the most challenging time of year for the poultry farming industry. Scientifically adjusting ventilation, providing nutritionally appropriate feed, maintaining stable conditions and temperature inside the house, routinely inspecting and observing the flock, and avoiding basic mistakes are among the foundations of successful poultry raising in autumn and winter. Only when the flock is stable and production performance is stable will the returns of poultry farmers remain stable.