Usually, the breeding eggs are not hatched immediately after they are laid. Breeding eggs must be stored for a certain period of time in the hatchery or in the breeder farm, and the breeder farm is often far away from its breeder farm and hatchery.
When the number of breeding eggs is quite large, they will be stored in the incubator, waiting for the incubator to have enough space to hatch. When the number of breeding eggs is limited, the hatching hall needs to store enough numbers to meet the huge incubator capacity. In summer, in order to prevent the production of the breeder farm from falling, the hatchery needs to store some eggs to meet the needs of summer production.
Breeding eggs are usually stored at a temperature of 12-18°C, which can cool the eggs and limit embryonic development. At the same time, the relative humidity is between 70-80% to prevent moisture loss in the breeding eggs.
The supervisor of the incubator should try to hatch the eggs after they are laid) after proper storage for 3-4 days, because the embryo mortality rate increases after the eggs are stored for more than 7 days. Previous experiments have also shown that storage of eggs for more than 7 days will affect the quality of chicks.
In order to improve the hatching rate of eggs stored for more than 7 days, many effective methods have been researched and invented. Such as adjusting different storage temperature and humidity; storing the breeding eggs in a sealed plastic bag; sealing the breeding eggs in the plastic bag and inputting oxygen, carbon dioxide or nitrogen; turning the eggs with the small end up; turning the eggs during storage.
One of the most successful ways to increase hatchability is to warm the eggs before storage.
As we all know, hatching after storing for a period of time, the hatching time needs to be lengthened. There may be two reasons why the incubation time is prolonged. On the one hand, the egg embryos that have been stored for a long time are not easy to develop under the normal incubation temperature. On the other hand, the stored embryos develop slowly in the initial stages of incubation.
The Poultry Research Center of a university in the United States is conducting experiments to investigate the effects of long-term storage of breeding eggs on embryonic development and hatchability, and to determine whether incubating for a period of time before long-term storage can increase the hatchability of modern broiler breeders.
1.Why does the stored egg embryo take a longer time to hatch?
According to the research done, it is determined that after a long period of storage, different eggs and embryos have different reactions. The embryos of some breeding eggs can develop at the same time as the embryos of breeding eggs stored for only 4 days. However, some embryos stored for 14 days are placed in an incubator at a suitable temperature but do not develop. These embryos do not develop right away, as if they need some recovery time to develop. After 14 days of long-term storage and capable of developing immediately after hatching, the growth rate of the eggs is later than that of the eggs that have only been stored for 4 days. It is determined that the embryo metabolism rate of the embryos stored for up to 14 days is slower than that of the embryos stored for 14 days. All in all, hatching eggs stored for 4 days have an average of 10 hours longer incubation time than hatched eggs stored.
2.In the first few days of storage, the hatching rate begins to decline? What is the cause of the drop in hatchability?
Storing the breeding eggs for 2, 4, 6, 8, 10, 12, 14, 16 days, and determining when the eggs are stored will affect the hatching rate. There is no difference in hatching rate between eggs stored for 2, 4, and 6 days. The hatching rate of hatching eggs stored for 8 days decreased significantly, about 7%. The hatching rate of storage for 10, 12 and 14 days is basically similar. The hatching rate of eggs stored for 16 days decreased by about 5%, and the embryo mortality rate increased from day 15 to day 21.
3.Can measures be taken to improve the hatchability of long-term storage eggs?
Previous studies on breeding turkeys have shown that incubating the breeding eggs for 12 hours before storing them for 14 days can increase the hatchability level to the same level as that of breeding eggs stored for only 4 days. The eggs of broiler breeders have also been tested to see if they will increase the hatchability. In this study, hatching eggs were incubated for 0, 6, 12, and 18 hours before being stored for 4 or 14 days, respectively. The theoretical basis of this experiment is that a certain stage of embryo development can well withstand the negative effects of long-term storage of breeding eggs. The test results are very encouraging. The hatching rate of hatching eggs stored for 4 days has no obvious influence on whether they are hatched or not before storage. The hatching rate of eggs stored for 14 days without hatching before storage is about 17% lower than that of eggs stored for 4 days. The good news tells us: if you need to store 14-day breeding eggs, the hatching rate can be increased by almost 10%. However, there is no benefit in incubating the eggs for a longer period of time before storing the 14-day eggs. The hatching rate after incubation to 18 hours drops to 11.5%.
The test results show that not all embryos respond the same to long-term storage. Under suitable incubation temperature conditions, some embryos stored for 14 days no longer develop, and other embryos begin to develop, but the rate is very slow. In most cases, some embryos stored for 14 days can develop normally. If we can determine why these embryos can develop normally, the positive factor is to ensure the normal development of long-term storage eggs through genetic selection.
The results of the test support the “critical point” argument: storage eggs should not be stored for more than a week. If the eggs are stored for 8 days or less than 6 days, the hatching rate will be significantly reduced. Therefore, all measures should be taken to ensure that the storage time of breeding eggs should not exceed 6 days.
As mentioned above, hatching eggs that need to be stored for 14 days can increase the hatching rate by almost 10% by incubating for 6 hours before storage. This result can be a good guide to further improve the hatchability of long-term storage eggs.
The current research is to find the best incubation time. If it is necessary to store the breeding eggs for a long time, before storing in the hatchery, after a certain period of time in the breeder farm and then incubating for a few hours, will the hatching rate have the same increase? This needs further study.
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