Embryonic Development in Poultry

Whether it is chicken eggs or turkey meat, many people around the globe can appreciate what we can get from poultry. However, to ensure that poultry sources remain an unlimited natural resource, their reproduction and development is key in maintaining their population. As a result, the embryonic development has been well studied with simplified information that anyone can understand.

  1. The Egg

    • The process of going from an egg to a bird is an amazingly complex yet short process. It begins with a yolk inside a hen being released through ovulation and traveling down a spiraling tube called the oviduct. In the oviduct, albumin (egg white) covers and binds the yolk. A layer of calcite is deposited around the egg white at the end of the oviduct to form the eggshell. For the initial embryo to exist, the egg yolk has to be fertilized by sperm in the oviduct prior to the eggshell phase. Special incubation conditions must be present in order for the embryo in the egg to begin development.

    Incubation

    • The conditions of incubation are crucial for the proper development of the embryo. In nature, the mother will usually sit on the eggs to keep them warm until they hatch. The eggs can also be placed inside an incubator controlled by people for commercial or educational reasons. The temperature and humidity levels around the fertilized egg are the most important factors in its development and different between species. For example, turkey eggs should incubate at around 37.7 degrees Centigrade with a relative humidity of 58 percent, whereas a goose egg incubates at the same temperature but with a lower humidity of only 55 percent.

    Development Milestones

    • There are major milestones in the embryonic development of poultry. As mentioned earlier, the amount of time differs between species. In a common chicken's case, the alimentary tract, vertebral column, nervous system, head and eye present themselves in the first day of development. On the second day, the heart and ear form with the heart beginning to beat in the latter part of the day. On the third day, the nose, legs and wings begin to appear. The tongue, reproductive organs, beak, feathers, scales and claws appear between the fourth and 13th days. Then the embryo begins to get into position to hatch while the scales, claws and beak become firm. If all goes well, the chick will begin pipping (pecking through the shell) on the 21st day.

    Hatching

    • The time from initial incubation and hatching varies between the types of poultry. Chicken chicks hatch in 21 days, goslings (geese) hatch in 28 to 30 days, ducklings (ducks) in 28 days, quail chicks in 16 to 18 days and poults (turkeys) in 26 days. The newly hatched chicks, goslings, ducklings or poults should remain in a warm place for about four to six hours to dry completely after hatching and until they become strong enough to walk around on their own.

    Complications

    • A variety of complications may present themselves during the developmental process. These are often because of problems with the temperature, humidity, unhealthy male chickens used in the fertilization process or poor ventilation. Complications can include dead embryos at different stages of growth, late or early hatching, embryos sticking to the shell, crippled chicks, small or weak chicks and abnormally short down feathers.