Fantastic page Holly! You have used pictures and diagrams really well to support your researched information. Grade


Embryo Development:

How does a chicken embryo develop during the 21 days of incubation?

A chicken remains as an embryo inside the egg for a total of 21 days while it develops, before it hatches. Here are some pictures and details of of the 21 days:

DAY 3: On the third day, the embryo's head turns on its left side and the tongue begins to form. The amnion surrounds it completely, the tail appears and the wing and leg buds can be seen.

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DAY 6: On the sixth day, the embryo's reproductive organs begin to form. The bones of the legs and the crop also begin to form.

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DAY 9: On the 9th day, the eye lids begin to cover the eyes and the knee caps begin to form.

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DAY 12: On the twelth day, the ribs begin to develop, the scales appear on the lower legs and the embryo continues to grow and move.

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DAY 15: On the fifteenth day, the embryo's scales, claws and beak become firm.

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DAY 18: On the eighteenth day, the embryo's beak breaks through the inner shell membrane and the mungs begin to function.

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DAY 21: On the twenty-first day, the chicken is ready to hatch and usually hatches on this day.

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Egg Fertilisation:

How does a chicken fertilise her eggs and how long does it take until the egg is laid?

Chicken eggs are fertilised inside the hen. The hens ovaries release a yolk which is then fertilised by a rooster's sperm inside the hen. The egg has to travel a long way through the various parts of the hen's reproductive system. Along the way it forms all necessary parts including the albumen (formed at the magnum), outer membrane (formed at the isthmus) and the egg shell (formed at the uterus) before is is laid. This process takes in total 24 to 26 hours before the egg is laid.

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What is an incubator and why are the conditions inside one important?

A chicken egg incubator is a piece of equipment used to replicate the conditions an egg would be in if it were being cared for my the mother hen so it can grow, develop and hatch. The machine has a trough of water to create humidity and tilts side to side to stop the chicken sticking to one side of the egg. It also provides ventilation to the eggs, helping them to develop. The right temperature must be maintained inside the incubator for the hatching of the eggs to be successful. A temperature of 37.5 degrees Celcius is recommended for incubating chicken eggs and humidity is needed. The chicken eggs hatch after 21 days like they would without being incubated since the conditions are set to be the same.

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Preparing Eggs for sale:

How are eggs processed so they are ready for sale?

There are seven stages in chicken egg processing so that they are ready for sale:
Receival: trucks deliver eggs from farms to grading floors. Eggs are taken to temperature and humidity controlled rooms so they are kept fresh until packaging. Eggs are washed and cleaned and are picked up by a suction to place them on a conveyor belt.
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Re- Oiling: When the eggs are washed, some natural oils are removed. These oils are necessary for helping keep the eggs fresh so grading floors send them to be re- oiled. A fine mist re coats the egg.
Country Egg
Country Egg

Quality Testing: Eggs are tested for good quality egg shells, yolk colour and egg white height. These eggs are only samples from when they were received on the grading floors. They are broken and measured and if they aren't up to standards, they are rejected.
Quality Assurance Testing
Quality Assurance Testing
First Quality Eggs
First Quality Eggs

Candling: The remaining eggs on the conveyor belt are passed over a light which looks inside for internal defects including blood spots and cracks on the shell or dirt spots. Once this process known as candling is completed, the defected eggs are removed and used in processed egg products instead.
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Stamping: Some eggs are stamped with a code showing details of the farm they have come from and they date they were processed. This helps the grading floors to trace eggs to their farm of origin if needed.
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Grading: Grades are the different sizes the eggs are sorted into. Once they are weighed, they are sorted and packaged depending on their weight. There are generally between three and five available sizes.
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Packing: Once graded, the eggs are placed in cartons and best before or used by dates are added. They then travel in their cartons by conveyor belt to the packaging area where they are moved to boxes and pallets so they can be transported to the storage area. They are kept in the right conditions before they are distributed.
Farm Pride eggs
Farm Pride eggs
Egg Grading and Packing
Egg Grading and Packing

Layer Chicken Breeds:

What are some different chicken layer breeds?

layer chickens are birds used only for producing eggs. Other chickens which are used for meat are called broilers. There are many different types of layers. Here are some of those breeds:
The White leghorn is a small bodied white bird which produces white eggs. It is considered a good egg producer.
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The Australorp is a heavy black bird with excellent laying qualities. It's eggs are creamy brown coloured and when this bird is crossed with the White leghorn, it produces eighty percent of commercial egg laying stock.
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The Rhode Island Red is a dual purpose bird which means it can be used for producing both eggs and meat. It is reddish black with yellow legs and produces brown eggs.
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The Brown Leghorn produces large, white eggs and is considered to be not as good a layer as the White Leghorn even thought they are similar except for their colour. It is small bodied with a black breast and tail and a brown neck and body.
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Chicken Parasites

Lice and mites are two types of parasites which effect chickens.
Lice are small, wingless, parasitic insects that live on the skin of mammals and birds. If chickens get lice, they need to be treated. This can be done by using a powder on the chickens when they have dust baths and making sure the nesting boxes and coups are cleaned out to help eliminate existing lice. The powder can also be used for spraying out the boxes. Some symptoms of lice on poultry are loss of appetite, lowered egg production and becoming more prone to illness.

Mites live on the skin of birds and nesting boxes. They suck blood from the chicken while it sleeps as they are nocturnal and they are very small and yellow/ grey in colour. (They become darker as they feed) Some symptoms of poultry mites include, loss of appetite, weakening, lowered egg production, sluggishness, weight loss and eventually death if not treated. Some treatments include insecticides, sprays and powders to be used on both the chickens and their nesting boxes.

Poultry Mites
Poultry Mites
Poultry lice
Poultry lice
Poultry lice
Poultry lice