What are the causes of a drop in laying rate in laying hens? Here is a detailed analysis
1. Disease aspects
?? ?After a flock is infected with an infectious disease, egg production will suddenly drop. When egg drop syndrome strikes, the flock often shows no obvious clinical symptoms; the main signs are a sharp drop in egg production and thinner eggshells, with more deformed eggs and brown eggs. The drop in laying rate usually reaches about 10%, and in severe cases about 50%. In addition, viral diseases such as Marek's disease, infectious encephalomyelitis, fowl pox, lymphoid leukosis and avian influenza, as well as various bacterial diseases, mycoplasma and parasitic diseases, will all cause a drop in laying rate. For viral diseases, prevention is key. A complete biosecurity system should be established, a reasonable immunization program should be drawn up according to local epidemic conditions, and a corresponding immune monitoring mechanism should be set up so that, based on the antibody levels of the flock, correct and timely prevention can be carried out. When disease occurs, in addition to emergency vaccination, nutritional drugs should be added to the feed to help the birds recover quickly. The control of bacterial diseases should focus on purification, hygiene management and disinfection. After disease occurs, timely diagnosis and symptomatic and causal treatment can minimize losses.
?2. Feed aspects
①An imbalanced protein-to-energy ratio, frequent changes in feed ingredient varieties, and use of poor-quality feed. For example: adding a very high proportion of cottonseed cake to the feed; suddenly switching from cooked soybean cake to raw soybean cake; suddenly switching from imported fishmeal to domestic fishmeal; using fake soybean meal, poor-quality fishmeal, fake amino acids, etc. All of these will greatly change the nutritional composition of the feed or make the feed less palatable, leading to a drop in egg production in the flock.
②Feed becoming moldy and deteriorated or being stored too long. In rainy weather, raw materials or feed are easily soaked or absorb moisture and cake during transport or storage, causing mold. In addition, after feed processing is completed, it has a certain shelf life. If feed is stored too long, especially in the high-temperature and high-humidity season of summer, many vitamins in the feed are very likely to decompose and lose effectiveness, and other raw materials are also prone to mold. This will inevitably affect feed quality and thus lead to disease.
③Inadequate feed processing management. During feed processing, negligence by workers often leads to excessive or insufficient addition of trace components such as salt, vitamins, trace elements and amino acids, causing nutritional diseases. In addition, sometimes due to unit failure, the particle size of the feed changes, which greatly worsens feed palatability; the hens are unwilling to eat, nutrition intake falls short of requirements, and egg production therefore drops. Therefore, in terms of feed, feed should first be formulated scientifically to ensure the nutritional needs of laying hens. Attention should be paid to raw material quality, ensuring they do not become moldy or deteriorate, and ensuring raw material varieties are rich and stable. Feeding moldy and deteriorated feed is strictly prohibited. In addition, the supply of vitamins and trace elements should be ensured, the calcium ratio in the feed should be appropriate, and feed changes should have a 3-5 d transition period to prevent indigestion in the flock and a resulting drop in egg production.
????3. Feeding management aspects
①Insufficient feed supply. Although some customers increase the feed to the standard amount, they do not consider the feed energy level, environmental changes, or the body weight of the flock at the start of laying, often resulting in an insufficient feed supply. In some cases, due to human factors, errors in calculating the feed amount or in weighing feed also cause underfeeding. In addition, when new and old workers switch shifts, or when too much feed is given at one time or the feeder is filled too full, more feed is wasted, all of which can cause insufficient feed intake in the flock and a drop in egg production.
②Insufficient water supply. When there is a power outage, the keepers forget to open the drinking water valve; low water pressure means water cannot be supplied; blocked water lines and other reasons prevent normal water supply. All of these can cause varying degrees of drop in egg production, and the harm to the hens is even more serious in hot summer.
③Temperature changes. The most suitable temperature for laying hens is 10-25 degrees. If the temperature is too low, especially in early winter when a cold wave suddenly arrives, the flock is stimulated by cold wind, causing feather loss and then cessation of laying. If the temperature is too high, especially continuous high temperatures in hot summer, feed intake of the hens drops sharply, nutrition falls short of needs, and egg production declines. In addition, the temperature difference within a day should not exceed 8 degrees, otherwise it will also affect changes in flock production.
④Unreasonable lighting. In rural areas, power outages are frequent and last a long time, and after power returns, lighting cannot be supplemented in time, causing the lighting period to suddenly shorten. Sometimes, due to negligence by the keepers, they forget to turn off the lights and the lighting period increases sharply. In addition, paying attention only to lighting duration while ignoring light intensity, and not wiping bulbs (tubes) for a long time, reduces light intensity. All of these can cause physiological dysfunction in laying hens and affect the normal expression of laying performance.
⑤Poor ventilation. Poor ventilation facilities, unreasonable design, or closing all vents in winter to keep warm cause harmful gases such as ammonia, carbon dioxide and hydrogen sulfide to accumulate in the house, which not only affects egg production but can also induce respiratory diseases. In addition, in summer, when temperature is high and humidity is high, if ventilation is not increased, laying hens will suffer heatstroke.
⑥Improper immunization and medication. Vaccination during the laying period, or continuous administration of antibiotics or deworming drugs such as oxytetracycline, chloramphenicol and sulfonamides for several days, will inhibit the rise in egg production due to stress and the toxic side effects of the drugs. At the same time, if the concentration of disinfectant in drinking water is too high, it will also cause poisoning reactions in the flock, resulting in a sharp drop in egg production.
⑦Stress factors. Wild birds and rats entering the chicken house frighten the flock and cause stress. At the same time, frequent replacement of workers on some farms, loud noises inside and outside the house, and sudden exposure to strong light also easily frighten the flock and lead to a drop in egg production. In feeding management work, in response to the above causes, strict rules, regulations and operating procedures should be formulated, management should be effectively strengthened, staff should be trained regularly, and the stability of keepers should be maintained as much as possible. Strict job responsibility systems should be established and reward and penalty systems strictly implemented to increase workers' enthusiasm and ensure normal production. The chicken house should be kept warm in winter and cool in summer as much as possible, attention should be paid to ventilation and air exchange, disinfection measures should be strict, and lighting management should be strengthened so that lighting is maintained at 16-17 hours and not increased or decreased at will. Artificial frightening should be prevented, and the flock should be provided with a quiet and comfortable production environment as much as possible, so as to ensure that laying hens are in good condition and can fully express their production performance.