Layer Production

Poultry - Sperm cells live for at least?

6 days or as long as 10-15 days

Young are developed inside a fertilized egg outside the hens body​

Oviparous

Young are carried inside the body

Viviparous

is a biological structure intended by nature for reproduction.​It protects and provides a complete diet for the developing embryo, and serves as the principal source of food for the first few days of the chick's life.​

Egg

The egg is also one of the ________________ of human foods.

most nutritious and versatile

Made of calcium carbonate, some material as seashell, chalk, and limestone.

Shell

Porous yet protective, moisture and air can pass through this

Shell

Made of protein, prevents bacterial infection

Inner and Outer shell membrane

Made of protein and water and protects the yolk

White (Albumen)

Made of fat, proteins, cholesterol, water, vitamins, and minerals. Contains lecithin, which is used as an emulsifier

Yolk

Protein strands, suspend the yolk in the white

Chalaza

Forms when the egg contracts as it cools after laying.

Air cell

Freshness indicator, _____ gets bigger as moisture leaves the egg

Air cell

It takes how many hours for chicken to produce one egg?

25-27 hrs

After the egg is completed it moves to the _________, stays in the _______ for a short time and is then expelled from the hens body

Vagina

In particular, the quality of the eggshell deteriorates with the?

age of the hens

A good-quality hatching egg has an?

oval shape with a large end (air cell end) and a clearly recognizable sharp end.​

The egg receives its particular shape because it is_________________________. It is also free of deformities. ​

pushed through the oviduct

At what age does calcium absorption in hens significantly decrease?

After 40 weeks of age.

What percentage of eggs can be damaged at the end of the laying period (65–70 weeks)?

Up to 20–30%.

What is the best age range for hens to produce hatching eggs with high fertilization rates?

35–43 weeks of age.

What is the fertilization percentage of eggs from 35–43 week-old hens?

Over 93%.

What are the ideal shape characteristics of a good hatching egg?

Oval shape, with a large end (air cell) and a pointed end.

What types of egg shapes are NOT suitable for large-scale hatching?

Too round or oblong eggs.

What tool is used to measure egg shape?

Vernier Caliper.

How is Egg Shape Index (ESI) calculated?

ESI = (Egg Width ÷ Egg Length) × 100

What is the optimal ESI range for hatching eggs?

Between 72 and 76.

What is the optimal ESI for chicken eggs?`

74

What is the optimal ESI for duck eggs?

72

What is the optimal ESI for quail eggs?

78

occurs, where water rich in electrolytes enters the albumen, and the formation of the mammillary cores begins. This stage lasts about 5 hours.

Plumping

Plumping happens in?

Tubular shell gland

reasons why shell strength is one of the key parameters in choosing strains for egg-laying production

• Preventing egg loss due to breakage.

• Reducing economic losses in production.

• Avoiding downgrading due to shell defects.

What causes economic loss in the layer industry related to shell strength?

• Eggs with weak shells break before reaching the store

• Broken eggs result in egg loss

• Egg loss is directly associated with weak shell strength

How can strong eggshells be ensured?

Through proper hen nutrition

Include in diet:

Calcium carbonate

Phosphorus

Magnesium

Organic minerals: Fe, Mn, Cu

What happens when eggs are downgraded?

• Given a lower score due to visible shell defects

• Affects marketability and price

How is shell strength monitored?’

Downgrading: eggs that are given a lower score due to visible defects​

• Measure internal egg quality

• Monitor strength of eggs produced

• Use candling to check eggs

It is the process of sorting eggs into Grade AA, Grade A, or Grade B based on their exterior and interior quality at the time of packaging.

egg grading

What are the three classifications of egg grades?

Grade AA, Grade A, and Grade B.

Covers a small area, white is firm with much thick white and a small amount of thin white. The yolk is round and upstanding.

Grade AA egg

Covers a moderate area, white is reasonably firm with a good amount of thick white and medium thin white. The yolk is round and upstanding.

Grade A egg

Covers a very wide area, white is weak and watery with no thick white. A large amount of thin white is thinly spread. The yolk is enlarged and flattened.

Grade B egg

The visual examination of an egg by holding it between the eye and a light source to test internal quality and freshness.

Candling

What can candling monitor?

Egg fertility

Embryo development

Weight loss rate

What is one benefit of candling non-viable eggs?

It prevents the risk of a rotten egg exploding and contaminating the hatch with dangerous germs.

How much weight should an egg lose during incubation?

About 13% of its original weight.

What happens if incubation humidity is too low?

The air sac becomes larger than normal due to faster water loss.

What happens if the air space is smaller than normal?

It indicates that humidity is too high.

What parts of the egg are observed during candling?

Air cell

Egg white (albumen)

Yolk

Spots and cracks

Candling can help reveal this, eggs with interior _____ should not be sold

Spots (blood/meat spots)

Hatching eggs will be subjected to candling thrice

1st candling - before setting the eggs

2nd - 6 to 8 days of incubation

3rd - 18th day of incubation

supplies food material to the embryo. ​

yolk sac

rms a sac that is filled with fluid in which the embryo floats. In this way it provides a shock-absorbing environment in which the fragile embryo can develop without harm from normal day to day knocks.​

Amnion

serves as a respiratory organ, gets minerals from the shell, and handles waste. It develops an extensive circulatory system connected to that of the embryo and is driven by the new embryonic heart.

Allantois

When the allantois is fully developed it completely surrounds the _______

embryo

Allantois has a number of functions:​

Respiratory, excretory, digestive

the developing embryo uses oxygen and produces carbon dioxide (it respires). It is unable to carry out this function for itself and hence the allantois oxygenates the blood and eliminates carbon dioxide.​

Respiratory - Allantois

it removes the wastes that result from the embryo’s metabolism and deposits it in the allantoic cavity.​

Excretory - Allantois

it provides the means for the embryo to access the albumen and the calcium of the shell.​

Digestive - Allantois

fuses the inner shell membrane to the allantois and helps that membrane to carry out its functions.​

​

Chorion

Chick embryo development

1. Day 1 – Appearance of tissue development.

2. Day 2 – Tissue development very visible. Appearance of blood vessels.

3. Day 3 – Heart beats. Blood vessels very visible.

4. Day 4 – Eye pigmented.

5. Day 5 – Appearance of elbows and knees.

6. Day 6 – Appearance of beak. Voluntary movements begin.

7. Day 7 – Comb growth begins. Egg tooth begins to appear.

8. Day 8 – Feather tracts seen. Upper and lower beak equal in length.

9. Day 9 – Embryo starts to look bird-like. Mouth opening appears.

10. Day 10 – Egg tooth prominent. Toe nails.

11. Day 11 – Comb serrated. Tail feathers apparent.

12. Day 12 – Toes fully formed. First few visible feathers.

13. Day 13 – Appearance of scales. Body covered lightly with feathers.

14. Day 14 – Embryo turns head towards large end of egg.

15. Day 15 – Gut is drawn into abdominal cavity.

16. Day 16 – Feathers cover complete body. Albumen nearly gone.

17. Day 17 – Amniotic fluid decreases. Head is between legs.

18. Day 18 – Growth of embryo nearly complete. Yolk sac is still on outside of embryo. Head is under the right wing.

19. Day 19 – Yolk sac draws into body cavity. Amniotic fluid gone. Embryo occupies most of space within egg (in the air cell).

20. Day 20 – Yolk sac drawn completely into body. Embryo becomes a chick (breathing in air cell). Internal and external pip.

Probably infertile (or very early death) when candled at 1/3 of the incubation period.

Clear when candled

Seen after 1/3 of the incubation period.

Fertile with red blood vessels

Indicates early death when candled after 1/3 of the incubation period.

Red or black staining

Sign of early death when candled after 1/3 of the incubation period.

Embryo with red blood “ring”

Indicates late death (1/2 or 2/3 through incubation period).

Dark outline with ill-defined detail

Due to hatch in 24–48 hours.

Live embryo with bill in air sack

Things you’ll observed when candling

• Clear when candled

• Fertile with red blood vessels

• Red or black staining

• Embryo with red blood “ring”

• Dark outline with ill-defined detail

• Live embryo with bill in air sack