Reasons for the Low Hatchability of Ostrich Breeding Eggs and Solutions

The following nine aspects may all cause embryonic development problems, leading to embryo death, weak chicks, stunted development, and high mortality. Researching and improving these triggers will improve hatching results.

(1) High inbreeding coefficient affects hatchability

A high inbreeding coefficient: inbreeding can lead to a series of decline phenomena, low hatchability of breeding eggs, malpositioned embryos, and high early mortality. Chicks have weak hatching ability, are unable to break the shell, and die inside the shell. Chicks are weak, mostly weak chicks, grow slowly, and have high mortality. When parents are unrelated, interbreed between breeds (such as Red Neck X Black Neck), or crossbreed between strains, vitality is strong and breeding egg hatchability is high.

(2) Poor nutrition of breeding birds affects hatchability

Nutritional deficiency in breeding birds leads to imbalanced nutrition in breeding eggs, causing early and mid-term embryo death or chick deformities during incubation.

1. Vitamin E and vitamin A deficiency obstructs and disrupts blood circulation, leading to embryo death.

2. Vitamin B12 deficiency causes thyroid enlargement, bleeding, edema, and blindness.

3. Riboflavin and biotin deficiency causes abnormal cartilage development, short bones, curled toes, and thin legs.

4. Vitamin D3 deficiency or insufficient phosphorus and calcium, or an imbalanced ratio, causes skeletal deformities.

5. Trace element manganese and zinc deficiency causes abnormal skeletal development, cartilage problems, short leg bones, and deformities.

(3) Breeding birds suffering from Escherichia coli, Salmonella and other infectious diseases affect hatchability

Escherichia coli and Salmonella can be transmitted vertically to breeding eggs. During incubation, even if the embryo develops fully, it dies in the shell during the late incubation period due to yolk infection and swelling. Hatched chicks have swollen abdomens, incompletely closed navels, inflammation, and low survival rates.

(4) Egg weight and quality affect hatchability

1. Weight of breeding eggs: as breeding eggs, the weight is generally preferably 1000—1500 grams. If the egg is too large (over 1600 grams), the air cell is relatively small, the embryo develops poorly in the late stage, hatching is difficult, or the chick is weak after hatching. If the egg is too small (under 900 grams), the chicks are mostly weak chicks with very low survival rates.

2. Egg shape: oval is best. Long eggs, pointed eggs, unusually round eggs, soft-shelled eggs, and deformed eggs have abnormal internal structures, affecting embryonic development and resulting in poor hatching results.

Egg shape is often expressed by the egg shape index. Egg shape index = short diameter of egg ÷ long diameter of egg x 100%. The smaller the index, the more the egg tends toward round; the larger the index, the more the egg tends toward long.

3. Shell quality: a good eggshell has a light cream-yellow surface evenly covered with a transparent, smooth, bright enamel membrane, and the air cell is at the blunt end (large end) of the egg. Pores on the shell are obvious, with many pores concentrated at the blunt end. Eggs with rough surfaces, lacking the enamel membrane and luster, thin-shelled eggs, and sandy-shelled eggs are easily contaminated under natural conditions. During incubation, such eggs can hardly perform the shell's function of protecting normal embryo development, and the embryo can die at any time.

4. Contaminated eggs: eggs soaked and contaminated by feces, urine, or rainwater allow harmful bacteria to enter the egg through the gas pores in the shell, harming embryonic development and easily producing rotten eggs.

(5) Improper handling of breeding eggs before incubation affects embryonic development and leads to early embryo death.

1. Temperature, humidity, and sanitary conditions in the egg storage room that do not meet standards affect embryonic development. The temperature in the egg storage room should be controlled at around 18 degrees Celsius and must not exceed 23 degrees Celsius, because 23 degrees Celsius is the critical temperature for breeding egg development. Above 23 degrees Celsius, embryo cells begin to divide and embryonic development proceeds slowly; such breeding eggs will produce weak or dead embryos after being set for incubation.

The relative humidity in the egg storage room should be controlled at 60%—70%. It must not exceed 80%. Humidity above 80% favors bacterial growth, makes breeding eggs prone to contamination, and affects egg quality.

The egg storage room must be disinfected regularly to kill pathogenic bacteria, maintain cleanliness and hygiene, and prevent breeding egg contamination.

2. Storage time of breeding eggs affects embryonic development. Practice has proved that the most ideal combinations of storage temperature and incubation time are: when the egg storage room is 18-20 degrees Celsius, breeding eggs are stored for 7 days before incubation; at a storage temperature of 16-18 degrees Celsius, no more than 15 days before incubation; at a storage temperature of 12 degrees Celsius, the incubation time must not exceed a storage period of 30 days. During this period, eggs must be turned frequently. If the above storage principles are not followed, the breeding eggs are stored too long, or the egg storage room temperature is high, embryonic development after incubation will be very weak and early embryo death will occur.

3. Using too much fumigation disinfectant or fumigating for too long severely irritates the blastoderm and can lead to embryo death.

(6) The effect of temperature and humidity during incubation on hatching results

Incorrect incubation temperature affects the activity of various enzymes in the egg, causing disorders in the development of various tissues and organs, affecting embryonic development, and even causing early or late embryo death. The quality of hatched chicks is also poor.

1. If incubation temperature is too high, the following will occur:

(1) Embryos develop quickly, hatch early, chicks are weak, and growth is stunted.

(2) Embryos have difficulty breaking the shell and often die inside the shell.

(3) Chicks often show neurological disorders such as ataxia.

2. If incubation temperature is too low, the following will occur:

(1) Embryos develop slowly, delaying hatching time.

(2) The chick yolk sac is not absorbed or is poorly absorbed.

(3) The chick navel is incompletely closed and inflamed.

(4) Residual egg white at hatching causes chicks to stick to shell fragments, which can injure the chick's skin.

(5) Chicks are small and weak, development is stunted, and mortality is high.

3. If incubation humidity is too high, the following will occur:

(1) Water in the egg is difficult to release (weight loss), and in severe cases this affects embryonic gas exchange, causes embryo edema, weak hatching ability, and death inside the shell.

(2) Most hatched chicks are wet chicks and weak, often with swollen abdomens, edema, incompletely closed navels, susceptibility to infection and inflammation, and high mortality.

4. If incubation humidity is too low, the following will occur:

(1) Chicks are weak and growth is stunted.

(2) Skeletal development is abnormal.

(3) The neck is bent.

(7) During incubation, too long an interval between egg turning or stopping egg turning affects hatchability

During incubation, if the interval between egg turning is too long or egg turning is completely stopped, malposition occurs, and deformed chicks such as chicks with curved necks and twisted toes or embryo death are likely to appear.

(8) Uncontrolled ventilation in the incubator affects hatchability

If incubator ventilation is uncontrolled, the balance of carbon dioxide and oxygen inside the machine is disturbed, oxygen supply is insufficient, and late-stage embryos suffocate and die.

(9) Power outages can cause embryo death

Power outages cause the incubator to stop running and the temperature inside the machine to drop. If the cooling period exceeds 3 hours, embryos die.

The hatchability of ostrich breeding eggs is a comprehensive indicator, and many factors affect it, but the most important are the quality of the ostrich breeding eggs and management during incubation. Doing the following well will greatly improve hatchability.

(1) Egg collection: breeding eggs should be picked up promptly after being laid. They must not be exposed to the sun for long periods, because high temperatures increase the temperature inside the embryo and can kill the embryo. In winter, breeding eggs must not be allowed to freeze. Do not pick up breeding eggs with bare hands; wrap them with a disinfected towel and send them to the incubation room immediately.

(2) Disinfection: there are two commonly used methods for disinfecting breeding eggs. One is washing eggs: before washing, gently brush off soil or dirt on the surface of the breeding eggs, then rinse or spray with a 1:600 Baidusha solution. After washing, let them dry naturally in the air; be sure not to wipe them with a wet cloth. The second is fumigation: during fumigation, the dosage and time must be well controlled. Generally, use 15 milliliters of 40% formalin and 7.5 grams of potassium permanganate per cubic meter, and the fumigation time generally does not exceed 17 minutes.

(3) Egg storage: after disinfection, breeding eggs should be placed in the egg storage room immediately. Breeding eggs are generally stored for no more than 7 days. When storing breeding eggs, the air cell should face upward. The temperature of the egg storage room should be controlled between 13-16 degrees Celsius, preferably not exceeding 17 degrees Celsius, and humidity should be controlled at around 45%, not exceeding 60%. The air in the egg storage room should circulate, and the eggs should not be turned casually during storage.

(4) Temperature: incubation temperature is the decisive factor for successful hatching. For example, high-temperature and low-humidity incubation can dry the inner egg membrane, tightly wrap the embryo, weaken intestinal embryo development, and lower the survival rate; similarly, low-temperature incubation prolongs incubation time and causes non-absorption of yolk before hatching, edematous birds, and so on, and the hatching rate is also low. Therefore, incubation temperature must not be lower than 36 degrees Celsius. Specific conditions should be managed according to different seasons, different incubation stages, and temperature differences between northern and southern regions.

(5) Humidity: incubation humidity is also an important factor affecting hatchability. If incubation humidity is too high, it easily causes edematous birds; if incubation humidity is too low, the embryo loses too much weight, causing the embryo to be weak and die. Incubation humidity is generally determined by the water loss rate of breeding eggs during incubation. The optimal humidity for breeding egg incubation is generally 22%. If humidity is too high, the air in the incubation room must be dehumidified.

(6) Ventilation and egg turning: ventilation and egg turning are also among the factors affecting breeding egg hatchability. Embryos need to breathe during development, taking in oxygen from the air and releasing carbon dioxide. Oxygen deficiency leads to embryo death and an increase in weak chicks. Both imported and domestic incubators currently used can ensure air exchange and will not cause oxygen deficiency, but the air entering the incubator must be fresh. In addition, to ensure breeding eggs are heated evenly and to prevent shell membrane adhesion, the incubator can be set to turn once every 2 hours (90-degree angle), or once every hour is also acceptable.

(7) Incubation equipment: since ostrich introduction in China, imported incubation equipment has been used continuously. From the perspective of hatching results, domestic machines can compare with imported machines, but because domestic incubation equipment has no dehumidification system, the air in the incubation room must be dehumidified.

In addition to the above points, incubation room staff must strictly observe environmental sanitation and disinfection rules. Staff entering the incubation room must shower, change clothes, change shoes, and step in disinfectant water. Non-staff must not enter the incubation room. Only in this way can the hatchability of breeding eggs be improved better and more effectively.