A letter to the poultry farmer: Development of the embryo

Dear Poultry Farmer
Dear Poultry Farmer,

Development of the embryo begins at the time of fertilization in the infundibulum of the oviduct and proceeds as the egg is formed until ovipositioning. As the egg cools, the rate of embryo development slows and it enters diapause.
Dear Poultry FarmerCareful handling of the egg is necessary to preserve the integrity and viability of the early embryo prior to incubation and further development. Eggs should be collected at least 3 times per day in normal temperatures and 5 times per day when temperatures are above 85°F. Frequent gathering reduces the probability that eggs become contaminated with bacteria from feces or nest materials, and prevents overheating of eggs in summer and chilling of eggs during winter.

Clean nest eggs should be collected first and submitted to the hatchery for incubation. Dirty nest eggs, cracked eggs, and floor eggs depress hatch-ability and should be collected and packaged separately.

These eggs are not suitable for incubation. Most contamination in hatcheries originates on the breeder farm. Egg selection is used to eliminate eggs that are less likely to hatch and produce quality chicks. Egg size is a selection criterion since unusually large or small eggs do not hatch as well as medium-sized eggs.

Overweight and underweight eggs can be removed by automated equipment. Round or elongated eggs and eggs with thin or wrinkled shells do not hatch well and should not be sent to the hatchery. Dirty eggs may be contaminated with yolk, dried blood, or feces and these should be removed and discarded.

Eggs are moved into an air-conditioned egg room for storage until they are picked up and taken to the hatchery. They should be held in storage on the farm for as short a time as possible. After being picked up from the egg room on the breeder farm, they are placed in an egg holding room in the hatchery and stored there until they are incubated.

Each day of storage adds one hour to the time required for incubation, so fresh and stored eggs should be set at different times. Diffusion of carbon dioxide and water vapour from the egg through pores in the shell contributes to loss in hatch-ability during storage.

After 6 days of storage, hatch-ability declines by approximately 0.5 to 1.5% per day. Eggs should be cooled to below 75.2°F and held at 75-80% humidity in the storage room. Cooling eggs below physiological zero for broiler breeder eggs (75.2°F) minimizes embryo development during storage.

The longer eggs are held in storage, the lower the recommended storage temperature. Pre-warming eggs prior to setting is advisable to avoid temperature shock to the embryo and prevent condensation of moisture on the external surface of the egg’s shell (egg sweating).

By: Godbold Chukwuebuka
Poultry Consultant
Poultry Evangelist 🐓
Poultry Specialist 


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