Reasons for decline in eggshell quality in late stages of laying hens

1. Age

After the peak egg production of laying hens, as the age of the flock increases, the quality of the eggshells will gradually decrease. This is because the physiological functions of the chickens begin to deteriorate and the intestinal absorption capacity of nutrients (calcium, trace elements, etc.) Decrease, the metabolism of nutrients in the body decreases.

The main manifestations are: the number of deformed eggs and broken eggs increases, and the thickness, color and gloss of the eggshells decrease. Research has found that zinc and manganese can increase the strength of eggshells during the later stages of laying hens, and organic trace elements are more effective than inorganic trace elements in increasing eggshell strength and reducing the egg breaking rate.

2. Environmental conditions

Temperature and humidity: Among environmental factors, temperature and humidity have a great impact on eggshell quality. Under high temperature and high humidity conditions, the feed intake of chickens decreases significantly, the quality of eggs also decreases, and the egg weight will decrease accordingly. The thickness of eggshells in summer is not as thick as that in spring and autumn.

Light: The most important thing for chickens during the laying period is light. Random changes in lighting can easily cause physiological disorders in chickens, resulting in a decrease in egg production rate, and the production of a large number of small eggs, white-shelled eggs, soft-shelled eggs, and broken-shelled eggs, resulting in a decrease in quality.

3. Stress

Temperature changes, chicken diseases, noise, fright, density, etc. can all cause stress. During the breeding process, stress cannot be ignored. In many cases, stress not only affects egg production rate, but also affects egg quality and damaged eggs. Specific manifestations include a decrease in egg production rate and an increase in deformed eggs, soft-shelled eggs, and damaged eggs. There are many types of stress and various plans should be made to avoid them during breeding.

4. Disease

Atypical Newcastle Disease and Egg Reduction Syndrome: The egg production rate of chickens will decrease by 10% to 50%, and brown-shell eggs will turn white, cracked eggs, and shellless eggs will increase, causing the hatching rate and fertilization rate to be greatly reduced. Even after recovery it is difficult to reach the original level.

Infectious bronchitis: Egg production drops sharply during the laying period, eggs with thick shells and deformed eggs increase, the albumen of some eggs becomes thin and watery, and the quality of the eggs decreases significantly.

Once the disease occurs in chicks, it will cause permanent lesions, resulting in the inability to lay eggs or deformed eggs when they reach sexual maturity, and the egg production rate will be 10%-20% lower than that of chickens of this breed. Research has found that during the recovery period of sick laying hens, it is feasible to use organic trace elements to improve cracked and thin-shelled eggs caused by the disease.

5. Feeding and management

Chaotic management: Employees have a weak sense of responsibility, frequent water and feed shortages, unstable lighting time, and frequent changes in feed formula may cause the quality of hatching eggs to decline.

Overweight: The fat deposited in the eggshell gland blocks the secretory function of the eggshell gland, making it easy to produce thin-shelled eggs and soft-shelled eggs, resulting in an increased breakage rate and affecting egg quality.

Improper medication use: The use of some banned drugs during the egg production period affects the egg production mechanism of chickens to varying degrees, resulting in a decrease in egg quality and a decrease in qualified eggs.

6. Feed nutrition

1. Calcium content is too high or too low

Laying hens need a large amount of calcium to form eggshells, but calcium in the feed alone is not enough. A lack of calcium in the diet will produce thin-shelled eggs or soft eggs. Therefore, if insufficient stone powder particles are added to chicken compound feed, the calcium content in the feed will be too low, which will have a negative impact on the formation of eggshells, resulting in thin-shelled eggs and soft-shelled eggs. However, excessive calcium content in the diet will reduce the palatability of the feed, affect appetite, and then affect the egg production rate. In severe cases, gout can occur in chickens.

2. Improper phosphorus content and calcium-phosphorus ratio

Phosphorus is related to the elasticity of eggshells. If the phosphorus content is too low, it will reduce the elasticity of the eggshell; if the content is too high, it will affect the absorption of calcium. Therefore, whether the calcium to phosphorus ratio is reasonable or not has a great impact on the quality of the eggshell.

3. Trace elements

Trace elements are essential nutrients for animals. They affect eggshell quality to a certain extent by directly or indirectly participating in many physiological and biochemical reactions in animals. Organic trace elements have the advantages of stable structure, avoid mutual antagonism, multiple absorption pathways, and high biological potency. Studies have shown that zinc hydroxymethionine and manganese have a very good effect on improving the strength and hardness of eggshells.

4. Vitamins

Vitamins (especially VE and VD3) are cofactors and promoters of calcium absorption. VD3 deficiency will affect the amount of calcium absorbed and thus the quality of eggshells. Lack of VD3 will affect the absorption of calcium and phosphorus even if the diet contains sufficient calcium and phosphorus. and metabolic disorders, resulting in small, deformed eggs, thin and soft shells, reduced egg production and hatchability, etc. In addition, timely addition to the diet can ensure that chickens can effectively obtain VD3 and VE.

5. Feed moldy

Feed becomes moldy due to poor storage. After feeding chickens, the liver and kidneys of chickens are damaged by aflatoxin, which destroys the metabolism of vitamins in the chicken body, resulting in poor disease resistance of chickens, reduced feed return, and weight loss. Egg production decreases and egg shells become soft.

6. Reasonable use of additives

Reasonable use of additives can improve egg production rate and eggshell quality. For example, Eucommia ulmoides leaf extract can act on the ovaries, enhance the reproductive performance of laying hens, and extend the peak egg production period; bile acids can promote the absorption of fat-soluble vitamins, thereby promoting calcium absorption and utilization, and significantly improving eggshell quality.