Virtual+Chicken SD

Summary

This presentation, supported by Byrne University's Poultry Science department and the USDA, explores the hen's reproductive system, detailing the formation of an egg from the ovary to oviduct. It explains the journey of the yolk through the oviduct's five sections, including albumin and shell formation. The video also touches on potential health risks from pathogens like Salmonella and the egg's final stages, including the formation of the air cell and its potential journey to a hatchery or food processing plant.

Takeaways

• 🐔 Most female birds have only one ovary, located to the left of the spinal column.
• 🥚 The yolk is the first part of the egg to form in the ovary and is composed of one-third protein, one-third fat, and one-third water.
• 🕒 It takes about 24 hours for an egg to travel through the hen's oviduct after the yolk is released from the follicle.
• 🔁 The albumin or egg white is laid down in the magnum section of the oviduct, where it forms a protective layer around the yolk.
• 🌀 The albumin forms spiral ridges in the magnum, causing the yolk to spin and creating the chalazae that keep the yolk centered.
• 🥚 The egg's shell membranes are deposited in the isthmus, which is the section of the oviduct following the magnum.
• 🕔 The shell gland takes about 20 hours to secrete the calcium carbonate that forms the egg's hard shell.
• 🕳️ The eggshell has pores that allow for gas exchange but prevent the entry of harmful bacteria.
• 🐣 The air cell of the egg is formed after the egg is laid, as it cools and the contents contract.
• 🏭 Fertilized eggs go to hatcheries, while unfertilized eggs are processed for consumption or used in food products.

Q & A

What are the main components of a hen's reproductive system?

The main components of a hen's reproductive system are the ovary and the oviduct.

How many ovaries do most female birds have, and what is unusual about hens in this regard?

Most female birds have two ovaries, but hens are unusual in that they have only one.

Where is a hen's ovary located within her body?

A hen's ovary rests against the back body wall, just to the left of the spinal column.

What are the five distinct sections of a hen's oviduct?

The five distinct sections of a hen's oviduct are the infundibulum, magnum, isthmus, shell gland, and vagina.

What are the building blocks of an egg yolk, and what is their proportion?

The building blocks of an egg yolk are one-third protein, one-third fat, and one-third water.

How long does it take for a follicle to grow from less than one millimeter to its mature size?

It takes one to two weeks for a follicle to grow from less than one millimeter to its mature size of 25 millimeters.

What is the significance of the infundibulum in the egg formation process?

The infundibulum is significant because it is the only part of the egg's journey where fertilization can occur if it is to happen.

How does the albumin layer protect the yolk inside the egg?

The albumin layer protects the yolk by forming spiral ridges in the magnum, which cause the yolk to spin and create pigtailed structures called chalazae that keep the yolk centered.

What happens to the egg in the shell gland, and how long does this process take?

In the shell gland, the egg is covered with a thin albumin, then a highly concentrated solution of calcium carbonate forms the shell, and finally, a cuticle is deposited. This process takes about 20 hours.

What is the purpose of the pores in the eggshell?

The pores in the eggshell allow gas to pass through, which is essential for the potential hatching of a chick.

What happens to the egg after it is laid and begins to cool?

As the egg cools after being laid, the inner portion contracts and forms an air cell between the two shell membranes, which is used by a chick for breathing before hatching.