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The function and science of the avian ear

May 6, 2012 By ChickenGirl Leave a Comment

Do Chickens have ears? Yes! And in this article I will explain how they work.

Even though chickens ears are seen only as small,  fleshy red or white earlobes, or auriculars (also known as ear coverts), the inner ear channels and amplifies sound, and plays a significant role a one of the senses.

Near the auriculars and below and behind the eye, the ear is located. The auriculars channel sound waves into the ear opening,  and towards the eardrum, a thin membrane that vibrates in accordance with the sound waves. The waves are passed down the columella, one of the smallest bones in the avian body, and transmitted to another membrane called the oval window via the cochlea in the middle ear. The cochlea is filled with fluid, and tiny hairs called cilia are attached to its walls. They move with the sound vibrations, as blades of grass do in the wind. Vibrations are translated into electrical impules, and sent to the brain via the auditory nerve.

When human cilia are damaged, they never re-grow, and so throughout life, hearing slowly decreases. The same happens in birds, right? WRONG!!! Birds can regenerate their cilia!!!

Avians also have semicircular canals, the saccule and utricle, which regulate balance, just as they do in humans.

I hope this was interesting, feel free to browse my website!

 

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Eni’s Rare Breed Chickens has as Twin Website!!

April 6, 2012 By ChickenGirl Leave a Comment

Enis rare breed chickens has a twin website!!!! It is called TX Stock Photos. It sells photos, graphics and videos, and has a wide range of subjects, but specializes in quality countryside and equine photos. You can visit it here.

It also has a blog, where regular information on photography, new camera releases and tutorials in using adobe photoshop is posted. You can visit the blog here.

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Banish Bad Behaviour!! How-to Have Harmonious Hens!!!

February 5, 2012 By ChickenGirl Leave a Comment

Banish Bad Behaviour!!

In general, chickens are social animals, living in peace and harmony. When a new bird is introduced, this harmony is temporarily disturbed as the hens squabble to sort out their pecking order. The pecking order is the heirachy by which chickens live. The hens have a little squabble, and the hen that wins is the dominant hen. She gets access to the food and water first, and can put any hen who dares confront her back in her place with a sharp peck. On the other hand, the lowest ranking hen gets to go to the food last, and can be pecked at by any hen. Because of this system, hens live in peace, but when the balance is upset, peaceful Poppy can turn into ferocious Frostie.

In this article, I will cover a few points of bad behaviour and give some tips on how to deal with it.

 

Excess noise

It is usually the cockerel who makes the most noise, while crowing, this can only be avoided by not keeping a cockerel. Cantrary to popular belief, it is not necessary to keep a cockerel to get eggs. The cockerel is only needed to fertilize eggs. Sometimes, a hen will make lots of noise, when she has layed an egg. If this is her habitual egg laying noise, it is not possible to stop her from making the noise, but a few steps can be taken to reduce the amount of noise she makes. These include:

  • Reduce boredom (see below)
  • Reduce stress
  • Practise good husbandry

 

Boredom

Overcrowding and small pens can cause boredom, which often manifests itself as feather pecking in adults and foot pecking in chicks. Chickens are attracted to red, (which is why feeder bases are often red), so if blood is drawn cannibalism can be the result. You should always keep some genitian violet spray handy because this is antibiotic, and stains the wound purple, to stop the chickens from attacking the hen.

Boredom can be prevented or alleviated by;

  • Scattering grain over the ground to encourage them to forage ‘naturally’
  • Hanging up bunches of green leaves for them to peck at
  • purchasing, and hanging up blocks of seed

 

Fighting

This often happens when two cockerels come in contact with each other. This is why cockerels should be kept apart. This takes place over hens, territory, etc.

Fighting can also be found with hens, when a new hen is introduced, for example. This is done to establish the pecking order. Once this is established and all the hens know where they stand, peace will return.

Egg eating is addressed here. Corresponding section highlighted pink.


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Function and Utilization of Essential Vitamins and Minerals in Chickens

October 25, 2011 By ChickenGirl Leave a Comment

Just like for us humans, to chickens, vitamins and minerals are very important for health. Lack of  of these, known as a deficiency,  causes problems, varying from something more minor such as decreased egg production to much more serious conditions, such as anaemia and death.

Chickens need all known vitamins and minerals, with the exception of Vitamin C.

Below is a list of Vitamins and Minerals, and the effects suffered by chickens in case of deficiency.

 

 

Vitamin/ Mineral

 Vitamin and Mineral Function Deficiency symptoms

Vitamin A (Retinol)

 Good feathering, egg production, reproduction Weakness, lack of growth, decreased egg production
Thiamine (B1) involved in enzyme systems, Loss of apetite, Death, chick paralysis
Riboflavin (B2) Essential in many enzyme systems Poor growth, poor egg production and curly toe
Pantothenic Acid Essential for Growth, hatchability, feathering Dermatitis and lesions on feet and around beak and eyes
Niacin Fat protein and carbohydrate metabolism Bowed legs, inflamed mouth cavity
Choline Fat metabolism, Fatty liver, poor growth
Vitamin B12 Growth, good hatchability Anaemia, poor growth, embryonic mortality.ss
Vitamin D Bone growth, egg shell production, Calcium and Phosphorus utilization Rickets
Vitamin E Normal reproduction and fertility. Antioxidant Enlarged hocks, crazy chick disease
Vitamin K Blood clotting, haemorrhage
Folic Acid Prevents perosis, good feathering Anaemia, poor feathering, poor growth, anaemia
Biotin maintains blood glucose levels, involved in carbohydrate conversion Perosis, poor hatchability
Below are some important minerals essential to chickens’ health
Calcium Important for healthy bones, and strong eggshells, and hatchability Soft shelled eggs, poor hatchability and rickets
Cobalt Activates enzymes, synthesises B12, needed for pyrimidine synthesis Slow growth, mortality, reduced hatchability
Copper Iron metabolism, controls the movement of iron anaemia
Iodine Thyroxyn synthesis, regulates neuromuscular functions goitre
Iron Important in haemoglobin formation, Transports oxygen anaemia
Magnesium energy metabolism, nerve impulse transmission Sudden death,
Manganese Important in the formation of bone cartilage Perosis, poor hatchability, bone shortening, bowing bones
molybdenum Synthesis of haemoglobin Deficiency rare, excess more common, causes reduction in copper availability
Phosphorus Component of bone, helps bone structuring Poor egg shell quality, rickets, bad hatchability
sodium Acid-base balance, salt balance dehydration
Selenium Antioxidant, increases vit. E absorbsion, Poor fertility and hatchability
Zinc Essential for over 2oo enzyme systems Short bones, poor feathering, poor eggshell formation

 

 

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Chickens respiratory system- science of breathing and lungs

October 16, 2011 By ChickenGirl Leave a Comment

Because of the energy required for flying,birds have a very high demand for oxygen. Even though chickens don’t fly much, they still maintain these characteristics.

When a bird inhales, half the air passes through bronchi to the posterior (back) air sacs, and the other half goes to the posterior (front) sacs and the lungs. That in the posterior sacs is emptied into the lungs, rather than alveoli, gas exchange takes place between the blood capillaries and the air ‘capillaries’ known as para bronchi. Compared to mammalian gas exchange, that that takes place in birds is much more efficient because the partial pressure is the same as that of the environment.

Their lungs are quite different to mammal lungs, because, rather than being a single ‘bag’ for air, they have air sacs spread around their organs, which keep the pressure of air in the lungs constant.

They have no diaphragm, and therefore air flows into the lungs and is pushed out by muscular contraction.

Located at the bottom of the trachea (windpipe) is the syrinx, the birds voice box, and as they exhale they can crow, cluck etc…

Hope you liked this post, please check ot my other posts!

 

 

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A chickens Brain- The Science

July 17, 2011 By ChickenGirl Leave a Comment

Did you know that chickens have a concept of the future?

Scientist used tho think that only humans and higher primates had brains with structure that is complex enough to allow forethought. The complex arrangement of the neurons, and the  fact that they have a concept of the future suggests that they are intelligent enough to worry. An example of this is shown when a strange person comes to the breeders house, puts them in a box and into a roaring creature with legs that go round and round (a car!!). They dont peck around happily, instead they make noises of alarm and worry what is going to happen to them. An even worse scenario is when they are stuffed into crates, loaded onto a lorry and brought to a slaughterhouse.  This is a terrible state for them to travel in, and they spend their time worrying what will happen to them.

The neocortex is the part of the brain that deals with complex thought. Chickens have one of these too.

An egg can only hold up to 200 calories, and many calories are needed for a big brain. This is why mammals go through the pain of childbirth, because they give their young a constant supply of calories, and their young grow a big brain. Despite possessing a tiny brain (about the size of a pea!!), chickens fit a lot into it. Their spinal chord, and some parts of the brain deals with movement, co-ordination and reflex, while the rest of the brain deals with memory, senses, future conceps and voluntary actions. This is quite a lot to fit into such a tiny brain!

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Chicken genetics

May 11, 2011 By admin Leave a Comment

Inside every living cell, there is a nucleus (plural nuclei). This is the cells powerhouse, it controls the actions of the cell. Nestled in the cytoplasm among mitochondria and glycogen granules, the chromosomes are found within the nucleus. These structures, which become clearly visible under a microscope before they split, otherwise rest as chromatin granuals. These control the organisms characteristics by means of genes. Lined up on every chromosomes are genes which control egg colour, eye colour and other traits. Chickens have 78 chromosomes, some being sex chromosomes (so called due to determining gender and sex linked characteristics) micro and some being macro chromosomes.

Cells divide by meiosis and mitosis. Mitosis is where the chromosomes replicate and line vertically up the middle. The chromosome and its replica are called chromatids. They cross over each other in the centre and are held together by centromere. The cell splits vertically and the daughter cells have the same amount of chromosomes as the first. Mitosis is used for growth in plants and animals and asexual reproduction in plants.

In meiosis the chromosomes replicate and line up in two vertical lines in the centre of the cell. One row moves right, the other left and the cell splits down the middle. The chromosomes arrange themselves across the middle of the daughter cell. The chromatids seperate and travel to opposite ends of the cell, and the cell divides again. After the dividing has finished, the result is four cells, each with half the original number of chromosomes. Meiosis is used for sexual reproduction, so that when the egg is fertilized, the chromosomes in the males sperm complete the set of chromosomes. If this didnt happen, then the number of chromosomes each individual posesses would double with every generation.

A cell with the full number of cells is diploid, while one formed by meiosis is always haploid.

The gender of the individual is determined by certain kinds of chromosomes and their genes. In  humans, females are homogametic, meaning that the two letters that represent their gene type are the same but  with chickens the cockerel is homogametic. A ZZ chromosome is male, while a ZW chromosome is female.

Sex linked traits are carried in one copy on non-homogametic genes, while the homogametic gene carries two copies. As the male carries the larger amount of copies, he is mostly responsible for traits such as egg colour in his chicks.

Principles; Basic poultry genetics

These are just some basics that are essential for hobby breeders, covering basic DNA and genes.

1) There are two strands of DNA, twisted into a double helix. At each ‘point’ in the DNA that we call genes, the gene is equal on both sides. This means that there can be one or two doses of the gene. One dose is known as heterozygous, two are known as homozygous.

2) The ‘ locus’ is a name given to the point where the gene  falls on the DNA. Sometimes, several related genes are found on the same locus, these are known as allelles. If there are two different genes on the same locus,  this is called a heterozygote. A homozygote is where two doses of one gene are found on the same locus (one on each strand).

3) ‘Sex linked’ is a term used to describe a gene found on the z-chromosome. The z chromosome from hens only affects her sons and is known as sex-linkage.

4) If there is one dose of dominant gene it will make an effect on the phenotype ( The way genes act and the effect they produce). One dose of recessive gene makes them a ‘carrier’ for the gene, but its effect is not displayed.

5) A multi-interaction gene is where several genes are needed to produce an effect. A good example is the gene for single lacing. Pg, Co and Ml are needed for the plumage to show that marking.

This is useful information, especially if you plan to breed or study avian genetics. I hope you found this feature interesting and educative.

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The Science and Anatomy of an egg

May 11, 2011 By admin Leave a Comment

Most people see it as a simple oval form, we eat it for brekfast, poached, boiled, scrambled or fried, to us it seems like an everyday thing, but an egg is more than that. It is a fascinating structure, and also contains the potential of life.
An egg is protected by a porus shell made up of calcite, a christalline form of calcium carbonate. It is semipermeable, meaning water and air can pass through via the thousands of tiny pores. The egg has a very outermost layer called the cuticle which protects ftom bacteria. On the inside of the shell there are two membranes. The inner and the outer membranes are surprisingly tough. They are made up partly of keratin, which is found in hair, skin and nails, and act as a bacteria barrier.
When the egg is freshly laid it is warm, but once it cools the contents shrink, leaving an air space between the two membranes. The air space grows larger as the egg ages, which is why incubated eggs have large air gaps when shone through with a candling lamp.
Inside these two membranes there is the albumen or egg white which is made up of water and many different liquid proteins. The ‘chalazae’ are twisted ‘ropes’ of protein holding the yolk and also acting as shock absorbers. This structure can be seen on a fertilized, unincubated egg. The viteline membrane encases and supports the yolk.
The yolk contains protein, fat, water (to a lesser extent) and vitamins and minerals. This is where the chick obtains nutrition. The yolk ranges from pale yellow to deep golden depending on breed and management. Chickens that roam freely and eat lots of green generally have golden egg colour.
The eggs colour ranges from white to dark brown, with green and blue hues as well. The pigment is the last thing that is added during its formation in the ovary and depends on breeding and genetics.
When the egg is laid it comes out of the vent. Both eggs and droppings share this opening but the set up and placing of various organs inside the hen ensures that the two never come in contact. There is also no urinary opening to complicate matters, a chickens urine is not liquid, it is the white part of the droppings, called urates. The sunshine that a plant absorbs makes it green, while the sunshine that the hen eats when she eats the plant makes her eggs yolk yellow. Battery eggs are have pale yolks, because the only sunshine the hen gets is that that her food contains.
The meat spot is a small deposit of blood sometimes found in the yolk. It gives no indiction that the egg is fertile, it is simply caused by the rupture of a bood vessel during the eggs formation. It is safe to eat but can be removed before cooking with the tip of a kife.
Occasionally a hen may lay an egg that has no yolk or a double yolk, this is the result of an unsynchronyzed production cycle an usually occurs at the begining or end of the laying period. A double yolked egg should not be used for breeding so if the egg is extra large don’t be tempted to use it.

Even when she is young, a hen has more egg cells than she will ever lay. These are rudimentary or germ cells. The egg ripens and a yolk forms around it in layers. It travels down the oviduct, and at this point would recieve sperm from the male. The chalazae are formed and a membrane covers the yolk.  Then, liquid protein called the albumen, or egg white is added in layers, the last one being firm and spongy as a shock absorber. Then, the shell is formed and in the last three hours pigment is added. During incubation the chalazae break, so the hen turns the egg occasionally to keep it centred.

I hope this article has expanded your knowledge, if you are interested in more science subjects, take a look at our The science behind a chickens eyes page and our chicken genetics page.

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The science behind a chicken’s eyes

May 11, 2011 By admin Leave a Comment

Recent scientific discoveries have shown that chickens eye sight is better than that of mammals (humans included) in terms of colour. A chickens retina (light sensitive structure) is organized in a complicated structure of interwoven mosaics, and the cones (colour sensitive) can detect colour spectrum that human’s cannot. While humans can detect red, green and blue wavelengths, most birds (chickens included) have receptors for red, blue, green, violet and ultraviolet meaning that they may see an entirely different dimension.. Where a human would see green dots, a chicken would see different coloured dots, depending on the varying amounts of ultraviolet light.
When light enters the eye through the pupil which expands and contracts to allow sufficient light through, it travels through the lens and is reflected at the retina .The chickens retina can detect not only detect some ultraviolet wavelengths but also has special motion sensors which allow them to see motion in a way that we do not truly understand.
If a chickens eye is viewed side on, you will see that they have a transparent ‘bulge’. This is called the cornea. Did you know that chickens have eyelids? Three infact. They have a nictitating membrane, which is between the other eyelids. It slides sideways over the cornea and cleans and protects the cornea with lubricating fluid from a duct that serves the same purpose as our tears. their bottom eyelid moves up to meet the top one when they close their eyes, but they only close these eyelids when they are sleeping.

If you like science subjects, why not look at our Chicken genetics page and our The Science and Anatomy of an egg page, or browse our The Science of Chickens category.

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