The egg is formed STEP BY STEP
The hen begins to lay eggs when it is 18-20 weeks old. The timing of the start of egg-laying depends on genetic and environmental factors, nutritional status, temperature and especially brightness and length of the day. Reduced brightness and day length means that the hens do not lay eggs – or at least not as many in the winter as in the summer – unless there is artificial light in the hen house. The production period A hen is taken out of production at the age of approximately one and a half years. The hen will lay somewhere between 250 and 335 eggs during its production period (depending on the type of production). This corresponds to approximately 16-20 kg of eggs per hen during a production period, which varies from 378 to 413 days. The egg’s journey through the hen Only the left ovary and fallopian tube work in hens. The fallopian tube is approx. 40-80 cm long and is divided into five sections, each with its own function.
10 | The egg is formed
1
The infundibulum nearest the ovary is 8-9 cm long, funnel-shaped and flexible so that it can pick up the egg (egg yolk) released from the ovary. The yolk is given a membrane – the vitelline membrane – and the strings that keep the yolk in the middle of the egg white (the chalazae) are formed. The egg stays in the infundibulum for 15-30 minutes. This is where fertilization takes place, if applicable.
2
The magnum is the largest part of the fallopian tube – approx. 30 cm. The egg white is formed here during the 2-3 hours it takes the egg to pass through this section.
3
The isthmus is approximate 10 cm long. Here the shell membrane is formed over the course of 60-75 minutes.
4
The uterus is 4-5 cm long. The uterus glands ensure that the egg white is 'inflated' with liquid to its final size while the shell is formed. Mineralization occurs slowly in the beginning. Later, up to 300 mg of shell material is formed per hour. Pigments are deposited last – on the outer shell. The entire process takes 20-26 hours.
5
The vagina is the outermost 8-10 cm long section of the fallopian tube, which flows into the cloaca to the left of the rectum. The vagina’s mucosa is very adjustable and is pushed with the egg out through the cloaca, so that the egg does not come into contact with the cloaca mucosa. The egg is covered by a thin layer of mucus, which dries and forms a membrane. This membrane prevents evaporation and protects against the penetration of microorganisms. The process only takes a few minutes.