What are the reasons for the higher embryo mortality rate in pigeons

There are two stages of high mortality during incubation: one is concentrated at 4 days of incubation and 23 days, and the other is within the two days before hatching. The reasons for increased embryo mortality can be divided into two major categories: external and physiological.

External causes

1. Nest abandonment. It is common for parent pigeons to abandon the nest while incubating, and this can occur at any stage of incubation, causing embryo death. The abandoned eggs can be transferred to foster parents within 24-36 hours, thereby saving such eggs.

2. Fright. For example, cleaning the pigeon loft or working night shifts on bright moonlit nights may frighten the parent pigeons and cause them to leave the nest.

3. Damage by insects and animals. Various pests and harmful animals such as lice, flies, mosquitoes, bedbugs, rats, etc., and the larvae of some beetles will bore into just-cracked eggshells to suck the blood of the squabs or directly feed on the squabs.

4. Unreasonable nest box structure. The nest box should preferably be cup-shaped so that the eggs being incubated do not roll away from under the parent pigeon's abdomen.

5. Disinfectants and insecticides. If sprayed disinfectants or insecticides enter the eggshell, they will kill the embryo. For this reason, it is best not to spread quicklime inside the loft. When spraying disinfectants, the eggs should also be covered as much as possible.

Physiological causes

1. Old, weak, or sick parent pigeons. When parent pigeons are old, weak, or sick, the embryo mortality rate is higher; for example, old pigeons and sick pigeons have a high mortality rate of eggs.

2. Breed and inbreeding. Some breeds or strains have a higher embryo mortality rate due to genetic reasons. In addition, inbreeding also increases embryo death.

3. Pathological changes. Iodine deficiency can cause goiter, making squabs weak or causing them to die at the time of pipping. Embryos infected with bacteria or other diseases will die. Embryos infected with Salmonella typhimurium often die in the shell during the last few days of incubation.

4. Egg retention in the oviduct. If an egg remains in the oviduct for too long, the embryo may die due to lack of oxygen. Frightening the hen during laying, malformation of the oviduct, endocrine gland dysfunction, etc., can all prolong the time the egg remains in the oviduct.

5. Abnormal eggshell. Whether the eggshell is normal has a great influence on embryonic development. If the eggshell is too thick, higher humidity is needed during incubation. For this reason, before the squab is about to pip, thick-shelled eggs can be soaked in water for a short time to soften the eggshell and make it easier for the squab to hatch. Thin-shelled eggs have an even higher embryo mortality rate during incubation than thick-shelled eggs.

6. Abnormal fetal position. If the embryo position is incorrect, the squab cannot hatch, and this situation is especially common in double-yolked eggs. Abnormal fetal position in single-yolk eggs often occurs in long and narrow eggs, or when the squab pips at the small end of the egg.