Breeding Egg Management Methods and Incubation Precautions for Shouguang Chickens
The Shouguang chicken, also known as the Cilun chicken. The Shouguang chicken is characterized by its large body size and large eggs. It is an excellent local dual-purpose meat-and-egg breed. According to the 1978 Shandong Province poultry [records]. “Shouguang chicken” meat is tender and rich in nutrients, and on the market, at a price 2-3 times higher than ordinary chicken, it has become a sought-after item in high-end guesthouses, hotels, whole-chicken restaurants and wedding banquets.
The Shouguang chicken originated in the rice-field area around Cijia and Lunjia in Shouguang, Shandong, and is also called the “Cilun chicken”. Its whole body is covered with glossy black feathers, it has a red single comb, large and alert eyes, black or brown iris, a black beak, and white skin. It has a large body and tall legs, strong bones, a long body and deep breast, a broad and flat back, and thick legs. The Shouguang chicken is tolerant of coarse feed, has strong foraging ability, and is rich in body fat. The average weight of a large adult rooster is 3.8 kg, and of a hen 3.1 kg. The age at first laying is 240-270 days, the annual egg production is 90-100 eggs, and the egg weight is 70-75 g; the average weight of a small adult rooster is 3.6 kg, and of a hen 2.5 kg, with annual egg production of 120-150 eggs, egg weight of 60-65 g, and eggshell color reddish-brown.
Breeding Egg Management Methods for Shouguang Chickens
1. Selection of breeding eggs. Breeding eggs must be selected from healthy and high-yielding excellent flocks in non-epidemic areas. Selected breeding eggs must be of moderate size, with normal egg shape and egg color; deformed eggs, sand-shelled eggs, and cracked eggs are all unsuitable as breeding eggs. The selection of breeding eggs is meticulous work and must be done carefully.
2. Storage of breeding eggs. The storage time for breeding eggs is 7-10 days, the temperature is 15-16°C, the humidity is 70%-75%, and ventilation is good. Breeding eggs should be stored on egg trays, with the large end facing up, preferably placed at a slight angle; if the storage time exceeds 7 days, the eggs should be turned once a day to prevent the yolk from sticking to the eggshell. Poor storage of breeding eggs has a great impact on the hatchability rate.
3. Disinfection of breeding eggs. Breeding eggs should be fumigated and disinfected before storage and before incubation. The disinfection equipment can be self-made: use small square wooden strips to make a cubic wooden frame, seal the top and the surrounding 4 sides of the wooden frame with plastic film, and leave the bottom side empty. Place the breeding eggs on egg trays and stack them layer by layer, then place the wooden frame sealed with plastic film over the egg trays. During disinfection, lift the plastic-film-sealed wooden frame by 10-20 cm, first place a ceramic or glass container containing formalin inside the wooden frame, then add potassium permanganate into the container, quickly lower the wooden frame, and fumigate for 20 minutes. For each cubic space, use 42 ml of formalin plus 21 g of potassium permanganate.
Precautions for Incubating Shouguang Chicken Eggs
1. After the breeding eggs are taken out of the storage room, they should be naturally pre-warmed in the incubation room; after the egg surface temperature reaches room temperature, they are placed on trays for incubation, with the tray placement position consistent with that during storage. In addition, the incubator should be cleaned, disinfected, adjusted, and pre-warmed in advance.
2. Requirements for incubation temperature and humidity: If the incubator sensor is placed in the space outside the egg trays inside the incubator, then after incubation begins, the incubator space temperature is 38.5°C on days 1-7, 38°C on days 8-18, and 37.5°C on days 19-21; if the incubator sensor is placed on the breeding eggs in the egg trays, then maintaining the egg temperature at 37.8-38°C from beginning to end is sufficient. Incubation humidity differs according to the incubator: for old-style incubators in which heating tubes are placed directly inside the incubator for warming, the airflow inside the machine is strong, so after incubation begins the incubation humidity is 60% on days 1-20 and 70% on days 21-24. For incubators heated by warm air with a relatively small fan inside the machine, after incubation begins the incubation humidity is 45% on days 1-20 and 60% on days 21-24.
3. Egg turning: From days 1-20 after incubation begins, eggs must be turned once every 2-3 h, 8-12 times per day, with a turning angle of 90 degrees, so that all parts of the embryo are heated evenly and the embryo is prevented from sticking to the shell. If the temperature difference among various parts inside the incubator is ±0.5°C, then the trays must be adjusted once a day, that is, the upper and lower egg trays are swapped, and the eggs around the edge of the tray are swapped with those in the center, to compensate for the effect of the temperature difference.
4. Candling: The first candling is carried out on day 7 after incubation; through candling, infertile eggs and dead embryo eggs are picked out. In fertilized eggs with normal embryonic development, the blood vessels are distributed radially and are bright and red in color; dead embryo eggs are lighter in color, contain irregular blood rings and blood arcs, and have no radial blood vessels; infertile eggs are bright with no vascular network, and only the shadow of the yolk can be seen. The second candling is carried out on day 17 after incubation begins, to remove dead embryo eggs, and live normal embryo eggs are moved into hatching trays and the hatcher. Live embryo eggs are dark red, with a tilted air cell, a curved boundary, and thick large blood vessels around them; around the air cell of dead embryo eggs, no dark red blood vessels can be seen, the edges are blurred, and some eggs are lighter in color with the small end bright. During the incubation process, embryo eggs should be sampled and inspected irregularly so as to grasp the embryonic development situation and take corresponding measures accordingly.
5. Transfer to hatching trays and hatching: When chicken breeding eggs have been incubated to day 18, the live embryo eggs should be transferred to hatching trays. After transfer, temperature and humidity should be controlled according to the temperature and humidity requirements for breeding egg incubation, that is, compared with the previous incubation stage, the temperature should be appropriately lowered and the humidity appropriately increased, to facilitate hatching. To ensure sufficient humidity, the number of water trays should be appropriately increased, and the water trays should be kept clean to facilitate water evaporation. Chicken breeding eggs begin to hatch on day 20 and finish hatching by the full 21st day. After the chicks break out of the shell, they should remain in the hatcher until their down is completely dry, and then be taken out and placed in a brooding room or box. If chicks are picked too early, the down is not yet dry and their adaptability to the environment is poor; if chicks are picked too late, after the down is dry the chicks can move about and may crawl out on their own and fall into the water tray and drown. During the hatching period, the lighting should be turned on as little as possible, and the light should be turned on only when picking chicks, so as to avoid damaging the joints when the chicks crawl. Generally, chicks are picked once every 2 hours.
6. Incubation management: During the incubation period of chicken eggs, temperature and humidity should be observed at fixed times every day (if they do not meet the requirements, they should be adjusted promptly), and records should be kept; generally, they should be checked and recorded once every 2 hours. Water should be added to the incubator's water trays at fixed times, and eggs should be turned at fixed times. Pay attention to ventilation and changes in instruments and indicators; if there are abnormalities, troubleshoot promptly. After each incubation task is completed, the incubator, hatcher and tools should be thoroughly cleaned, scrubbed and disinfected.
7. Inspection and analysis of incubation results
After each incubation is completed, the incubation results should be calculated (hatchability rate of incubated eggs, hatchability rate of fertilized eggs) and analyzed, so as to summarize, accumulate experience, and improve the level of incubation technology. Generally speaking, for artificially raised breeding chickens, infertile eggs at the first candling should not exceed 5%, and dead embryo eggs should not exceed 3%. If the dead embryo rate is too high, it is mostly due to improper storage of breeding eggs, or incubation temperature being too high or too low. If there are too many infertile eggs, it is mostly due to improper male-to-female ratio in the breeding flock, disease in the breeding chickens, weak male vigor in roosters, and lack of ejaculation ability, among other causes. At the second candling, a dead embryo egg rate not exceeding 3% is normal; too many dead eggs are often caused by poor feeding of breeding chickens, insufficient embryonic nutrition, unsuitable incubation temperature, and poor ventilation. In the late incubation period after transfer, dead embryo eggs are 6%-7%; if the number of dead embryo eggs is too high, it may be due to poor incubation conditions in the middle and late stages, mainly manifested as many dead embryos that peck the shell but cannot emerge. When collecting chicken breeding eggs, from collection until incubation, human-induced adverse interference should be minimized as much as possible to ensure a relatively high hatchability rate.