Laying Hen Husbandry and Management and Egg Safety

The peak laying period of commercial hens has the most direct impact on farming profitability. Many producers hold misconceptions or even incorrect beliefs about managing this critical phase, making proper management during the peak laying period essential.

I. Nutritional Measures During Peak Periods

During the peak laying period, from 20 to 40 weeks of age, the egg production rate exceeds 90%, and egg weight ranges from 40 to 56 grams. Hens gain body weight rapidly; white-shelled layers increase by approximately 5 g per day, with their body weight rising from about 1,300 g to 1,700 g, resulting in a stepwise increase in egg production. During this phase, it is essential to maintain the highest possible peak production and maximum egg weight. Energy intake is a critical factor influencing the egg production rate, as hens can adjust their feed consumption in response to energy availability. Research indicates that egg production rises sharply with increasing energy intake, particularly when protein intake is reduced. Therefore, adequate energy levels in the peak‑laying formulation are paramount; the diet must provide sufficient energy. If daily energy intake falls short of requirements, adult hens may fail to meet target levels for egg production, egg weight, and body weight. Consequently, accurately monitoring and managing feed intake in laying flocks is a key challenge.

In China, feed formulations for laying hens place considerable emphasis on protein supply. However, higher protein levels (including essential amino acids such as methionine) in the hens’ diets only contribute to increased egg weight; excess protein is partially converted into energy, resulting in waste. Meanwhile, energy intake is the primary limiting factor for increasing egg production. For laying hens, when dietary protein exceeds 13 g per day, energy intake becomes the dominant constraint on performance. Raising dietary protein from 13.1% to 20.7% has little effect on egg production rate; yet, at a low protein level of 13.1%, increasing energy intake from 184 kcal to 312 kcal boosts the egg production rate from 45% to 85%. Therefore, when insufficient energy intake is the limiting factor, even increasing protein content will not enhance egg production.

In production, insufficient energy intake is a common issue; when dietary energy levels drop to a point where hens are physiologically unable to consume enough feed to meet their energy requirements, egg weight declines first. At this stage, proteins and amino acids are diverted for energy use, thereby impeding their incorporation into egg mass.

In addition to increasing feed intake, a low dietary energy level can impair egg production when energy is insufficient to meet requirements even with increased consumption. A common example is the decline in laying performance observed each year when newly harvested corn has excessively high moisture content.

Consequences of insufficient feed energy:

1. Hens have a light body weight, resulting in delayed onset of laying;

2. After the peak, egg production declines.

3. Hens molt earlier;

Measures to increase feed energy:

1. Select high-energy feed and minimize the use of low-energy ingredients such as secondary flour and wheat bran; avoid, as much as possible, energy-free materials like maifanite, zeolite, and bentonite.

2. Addition of fats: enhances energy content, improves palatability, and reduces dust; meanwhile, it results in lower heat increment of feeding. Bacitracin zinc also decreases heat production, a effect that is particularly pronounced under high-temperature conditions, thereby significantly boosting the productive performance of laying hens.

3. Use high-oil corn

4. Use enzyme preparations: cellulase, hemicellulase, pentosanase, β‑glucanase, pectinase, and other enzyme products to enhance the metabolic energy of poultry.

Egg production rate is highest between 32 and 36 weeks of age, after which it gradually declines; this may explain why amino acid requirements are particularly high during the period from the onset of egg production to peak yield. It is recommended that amino acid requirements during this phase be set at 130% of the NRC standard.

Before 50–54 weeks of age, egg weight increases rapidly with age. Consequently, hens produce their largest eggs during this period. The relative amino acid requirements compared to the NRC standards are as follows: 130% for 20–30 weeks of age; 115% for 30–60 weeks of age; and 100% for 60–80 weeks of age. Adjust the feed formulation accordingly.

Principles for the prevention and control of diseases during the peak egg‑laying period: minimize stress in the flock, implement regular vaccination, and strengthen preventive measures against common diseases. During vaccination periods, astragalus polysaccharide can be administered periodically to enhance vaccine efficacy, bolster the birds’ immune defenses, and reduce the incidence of disease.

II. Post-Peak Management

After the peak period (at 36–40 weeks of age), egg production has declined, egg weight has increased only modestly, and body weight has stabilized. At this stage, it is advisable to moderately reduce the nutritional level of the feed to prevent excessive fatness, which can lower feed efficiency and raise rearing costs. After 40 weeks, the laying rate begins to drop, declining by approximately 0.7%–0.8% per week. Body weight no longer increases and approaches adult levels. Egg weight continues to rise throughout the laying period, with a more rapid gain during the first 15 weeks followed by a slower rate thereafter. Even after the peak, egg weight keeps increasing, eventually approaching the annual average. However, because the decline in laying rate outpaces the increase in egg weight, daily egg production tends to decrease following the peak. In addition, for breeds that exhibit high feed intake and are prone to rapid weight gain, a mild restriction feeding regimen may be applied: for white-shelled layers, restrict intake to 93%–94% of ad libitum consumption, or maintain a target intake of around 100 g per bird. Restrictive feeding should reduce energy supply while ensuring adequate provision of other nutrients as required. It is important to raise the calcium level to 4.5%. Typically, each hen should receive 3.45 g of calcium per day during the peak laying period, and 3.50–3.75 g per day during the later laying phase, to meet the calcium requirements for optimal eggshell quality.

During this stage, appropriately reducing the dietary protein level—by less than 1% per reduction—can result in a decrease of approximately 1.2 grams in egg weight.

Medication throughout the entire laying period has a significant impact on egg quality; therefore, selecting appropriate drugs for health maintenance and preventive care is crucial. It is essential to adopt a preventive‑first, prevention‑over‑treatment mindset and implement targeted control measures tailored to each season. In summer, when the incidence of intestinal inflammation and diarrhea is high, regular use of formulations such as Sihuang Zhili Granules or Bai Touweng Oral Liquid can help prevent and manage these conditions. During the winter and spring, when large temperature fluctuations increase the risk of viral diseases, consider using Shuanghuanglian or Banqing Granules for prevention and control.