Leghorn

Leghorn can be defined as a breed of chicken, these are normally categorized as commercial chicken breeds because of their excellent ability to lay eggs. The leghorn chicken breed is originally thought to be originated during the 12th century in the countries like Italy. The leghorn chicken breed is not widely preferred for their body meat. There are about 12 varieties of the breed of the leghorn chicken available, but the most common breed of them all is the white leghorn. They are most popular because of their prolific capacity for laying eggs. This article focuses on the general characteristics of the chicken and hen, their taxonomical classification, the distinct morphological feature of the breed, the diet, the reproduction pattern. The article also dwells on the commercial importance of the chicken breed.

General Description of Leghorn

Leghorn is defined as a type of breed of chicken and hen. The leghorn hen and chicken are also considered as a Mediterranean breed. The specialty of this breed is its ability to lay eggs. They lay a higher number of eggs in comparison to the other breeds of chicken. Apart from their ability to lay eggs another characteristic feature of the breed is their low body weight hence they are not suitable for meat production. The physical description of the Leghorn chicken breed can be referred to as a small size body chicken, they have red wallets, these wallets are large. The earlobes and the legs have similar characteristics as the other members or breeds of chicken that is they have white earlobes, and the colour of the legs are yellow as seen in most chickens. The comb of the leghorn is also used as a morphological marker, the leghorn chicken can have either a single or rose comb. The size of the comb also varies, they can either come in normal or standard size or bantam sizes. Apart from the white leghorn, another variety of leghorn that is commercially important is the Brown Leghorn, these have a large body as compared to the white leghorn thus are used in the meat production industry.

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Taxonomic Classification

The taxonomic classification can be described as a method of characterizing different animals and plants based on their similarity and dissimilarity. This technique of classification is also used to determine the phylogenetic relationships between different animals and species. The taxonomic studies also provide the basis of the evolutionary details, it can be said that the taxonomic classification is based on the evolutionary history of the organism.  The taxonomic classification of chicken is mentioned below.

The chicken belongs to the kingdom Animalia, this kingdom consist of all the multicellular eukaryotic organisms. The kingdom is further classified according to the similarity of organisms. The kingdom is further classified into phyla, the chicken belongs to the phylum called Chordata, the specific characteristic is the presence of the notochord in the animals that are categorized into this phylum. The phylum is characterized by the presence of 5 characters during any point of their complete life cycle, these 5 factors are as follows, presence of the notochord, presence of dorsal hollow nerve cord, presence of endostyle or thyroid, presence of pharyngeal slits, and the presence of a post-anal tail. All these 5 synapomorphies are present in the chicken thus qualifying them to be categorized as chordate.

The leghorn hen or as matter of fact every breed of chicken ae classified as the Aves. The phylum is further classified into classes according to the taxonomic classifications. The chickens belong to the class of Aves. although this class typically contains birds whose primary feature is their aviation ability, chickens are categorized as flightless birds. The loss of the ability of flight appeared as a result of the selection of certain traits as adaptation during the course of evolution. The main characteristic feature that is required to be classified under this category is the presence of feathers, toothless beaked jaws, the ability to lay hard-shelled eggs, a four-chambered heart, and a strong yet lightweight skeleton.  Another important feature of this class from the physiological point of view is the high metabolic rate, and they are warm-blooded animals. All these features hold true for the Leghorn breed of chicken.

The class is further classified into order. Chickens belong to the order called, Galliformes. The members classified under this class are primarily flightless birds, that live on the ground rather than building nests. Another characteristic feature is that members of this class generally has high body mass compared to other aves. The most important and well-known member of the class includes chickens, turkey and quail, and other landfowl. They are also considered important seed dispersers are predators of the area they inhabit. The class is majorly domesticated by humans as they have commercial importance.

The class is then categorized into the family Phasianidae, the most important members of this family includes pheasants, partridges, junglefowl, chickens, turkeys, and quails. The family contains majorly high body mass terrestrial birds as the members of the group. The distinctive morphological features of this family member generally include a plump body, with broad, relatively short wings and powerful legs. Another important point to note here is that this family contains members that are sexually dimorphic in nature. Sexual dimorphism is defined as the distinctive morphological features of males and females, based on which they can be differentiated. This is also true for Leghorn chickens where than males are larger than females (leghorn roosters are larger than leghorn hens). 

The family is classified into genus, and the genus contains different species. The Leghorn breed of chicken is the type of chicken that are selectively bred within the members of the same species. The chicken belongs to the genus Gallus. There are 4 living species that are classified under this genera and one of them is chicken. The four different species are as follows, Gallus sonneratii, Gallus lafayette, Gallus gallus, and Gallus varius. The leghorn chicken belongs to the species G. gallus. According to the trinomial nomenclature, the scientific name of leghorn is Gallus gallus domesticus.

General Classification of Leghorn

The general classification of leghorn is done on the basis of the size and comb type. This classification is performed by the American Poultry Association (APA). The summary of the classification is as follows.

Bantam and Large Fowl (Single and Rose Comb)

This Includes the Following Variety of the Leghorn Chicken and Hen

1. Black Leghorn

2. Buff  Leghorn

3. Dark Brown  Leghorn

4. Light Brown  Leghorn

5. Silver  Leghorn

6. White  Leghorn

Bantam (Single Comb Only)

This Category Includes the Following Leghorn Hens

1. Barred Leghorn

2. Black-Tailed Leghorn

3. Columbian Leghorn

4. Golden Leghorn

5. Red Leghorn

Physical Description

The physical features of the chicken that belong to the Leghorn breed can be defined on the basis of the comb, feathers, colour of the body, and size of the body. The basic anatomy of any breed of chicken is the same as they belong to the same genus and family. The characteristic feature of the morphology is the presence of large and flappy wings and combs. These large and floppy combs are also important appendages for heat regulation, due to their large surface area they allow maximum heat exchange and helps in cooling the body temperature during the summer seasons. But there are cons to the large combs especially during winter, they lose more body heat leading to the requirement of more care and facility.

They also have comparatively large wallets. The body mass of the bird is not very large. They are generally not bred for their meat. The body of Leghorns are quite slender and their back has a pronounced U shape profile. They have an upright stance and their tail is held fairly high. The bodyweight of the leghorns differs among males and females as a result of sexual dimorphic nature, Leghorn Hens weigh nearly up to 5lb whereas the body weight of the male, that is Leghorn Roosters can range up to 8lb. 

There are different colours of Leghorn chicken, based on the colour of the body the differentiation in the variety of the breed can be done. The leghorn varieties are of the following different colours, white leghorn, brown leghorn, black leghorn. According to history, the brown leghorn was first bred but the white variety of the leghorn is more popular.

The comb of the leghorn chicken is large, they can be single or can be present as a rose comb. The APA (American Poultry Association) classified leghorns on the basis of the comb, the common morphological feature is the presence of the yellow coloured legs. The earlobes of the bird are generally of white colour.

An important characteristic of the morphology during the early development stage, that is egg stage is the colour of the shell. The shell of the Leghorn hens egg are completely white, they have no yellow traces that are seen in some breeds of chickens.

Habitat 

The Leghorn breed of chicken is a domesticated breed they are able to survive under human protection. The chicken family in general have large geographical distribution areas, they are almost found in every landmass except for the polar regions of Antarctica. This holds true for the Leghorn breed also, they are found in every country except Antarctica, the most preferable habitat of leghorns are those that have a warm climate. 

Social Behaviour

The social behaviour of the leghorns is defined on the basis of their association with members of the breed. They are generally considered as an independent breed, they prefer to live in solitary. The Leghorn male members are quite aggressive in nature. One of the specialities of the leghorn is that they feed freely in an open environment. They require a large area for forage and are generally seen consuming less amount of food.

Another significant characteristic is the noise that these birds produce. Leghorns are described as quite noisy breeds of chicken, many animal experts consider this as a way of communication but the apparent meaning of the noise produced by the bird is still unknown. According to the research, the crowing (sound produced by the leghorn rooster) is a loud and sometimes shrill call. This call is considered a territorial signal to other roosters. Another reason for crowing may include creating awareness of a potential threat, they may also crow in response to sudden disturbances within their surroundings. 

The sound produced by Leghorn Hens is known as a cluck. Hens cluck loudly after laying an egg, and also to call their chicks. Chickens also give different warning calls when they sense a predator approaching from the air or on the ground

They are not a broody breed. Broodiness can be defined as a desire to have children, this not seen in the Leghorn breed. While broodiness is not an uncommon feature among chickens, the exact reason for this behaviour is still unknown. It is commonly seen that breeds that are selectively bred for commercial uses are not considered broody breeds. Another reason complementing this behaviour is the lack of parental care among this breed when compared to some other breeds. The leghorn hens are not considered as a good mother. It is because they do not provide complete protection and hatching requirements to the eggs.

Reproduction

The Leghorn breed is considered as a developed animal, they produce their progeny via sexual reproduction. Common to the general behaviour of aves these birds also lay eggs. Due to their egg laying ability they are termed as ovip[arous animal. The reproduction is internal. Internal fertilization refers to the process of fusion of male and female gamete that is sperm and egg within the body of the female. The fertilization leads to the development of the zygote. 

The embryo is laid out in a protective covering and this structure is known as the egg. The egg then develops into a chicken outside the female body but in the encapsulated area. The egg contains all the enzymes and the proteins necessary for the early and late developmental stages of the embryo. 

Since the fertilization process is internal, there is a definitive need to transfer the male gamete into the female body, this occurs by the process called “cloacal kiss”. It can be defined as the transfer of sperm into the female body through cloacal contact. Cloacal can be anatomically defined as the posterior orifice that works as an opening for the digestive, reproductive, and urinary tracts. This structure is commonly found in all the animals that are classified as aves, it is also seen in amphibians and some mammals.

Reproduction is controlled by the neuroendocrine system of the body. The neuroendocrine system can be defined as an association between the neural cells and endocrine glands or cells. The nerve cells send the message in the form of the impulse to the endocrine cells, as a response to this stimulus the endocrine cell releases the hormones that in turn regulate the sexual reproduction of the leghorn hen. The main hormone that is responsible for this regulation is Gonadotropin-Releasing Hormone-I, which are produced by the neurons in the hypothalamus of the brain.

The gonadotrophin releasing hormone (GnRH) in turn is involved in the up-regulation of the sex hormones of the chicken. These hormones include luteinizing hormone and follicle-stimulating hormone that regulate the production of estrogen, progesterone (sex hormone). The sex hormone is produced by the reproductive system and controls the reproduction process.  

Egg Production

It is a well-understood fact that leghorns are commercially bred chickens, the main purpose of breeding these chickens is their phenomenal capacity to produce eggs. On average, there are bout 280 to 320 eggs are produced per year. The leghorn chickens set the bar for productivity. The weight of individual eggs is about 55 grams which are approximately about 2 ounces. The eggs are of pure white colour with no visible spots or stripes. The leghorn hen can lay eggs up to its fourth or fifth year. The sexual maturity of the pullet can be seen with 4 weeks of hatching. After attaining sexual maturity they can lay eggs.

Diseases 

Although the leghorn breeds are considered as a strong independent breed but still they are subjected to some of the common diseases that are found in the other breeds of the chicken. They are commonly subjected to parasitic infections like lice, mites, ticks, fleas, and intestinal worms, these may not be fatally harmful to the animal but if not taken care can severely decline the health of the chicken, the members infested with such parasitic animals tend to be less productive. Tht is the number of eggs produced can decrease or the overall health of the chicken may also decrease, this also makes them unsuitable for the human consumption. (some of the varieties like brown Leghorn chicken are also used for their meat for human consumption.) 

Chickens also act as vectors, that is they carry parasitic microorganisms that infect another organism on consumption or contamination. One such example is Salmonella, the salmonella is a common pathogenic bacteria that gets transmitted from the consumption of infected chicken. It is one of the most common examples of a disease that gets transmitted through chickens. The pathogenic bacteria can also be transmitted by contaminated faecal matter. 

Another common disease that affects almost every chicken breed including the Leghorn chicken is bird flu. The bird flu is caused by a pathogenic virus called Avian influenza, this gets transferred to healthy through contact transmission. It is a fatal disease, recent researches have proved that this virus can be transferred to other cattle animals like pigs and turkeys. 

The List of Some Common Diseases are Mentioned Below:

1. Bumblefoot

2. Speed growing

3. Mushy chick disease

4. Salmonella

5. Yeast infection (thrush)

6. Gumboro

7. Syngamus trachea

8. red mite 

9. Blackhead disease

10. Paralysis

The Leghorn breed of chicken is a domesticated breed that is generally bred to produce a large number of eggs. The leghorn is available in 12 different varieties out of which the white leghorn and the brown leghorn are the most common. The white leghorn can produce about 320 eggs per year. The brown leghorn has a slightly high body mass thus is bred for its meat. Leghorns are an independent breed that does not require much human care. They can inhabit almost every landscape except for the cold polar regions. The speciality of the leghorns is their rose and single comb, with big flappy walters. They are also susceptible to common diseases like bird flu, lice and mite infection.