#layer hens

Most layer hens are purchased from  primary breeder companies in which eggs or more commonly new-born chicks are sexed and divided based on sex-linked physical traits. Female chicks are sold to become commercial layers themselves. Male chicks are slaughtered as a by-product of the industry, as they are not genetically nor phenotypically viable for meat production.

Chicks are then transferred to rearing facilities for around 18 weeks where daylight is controlled in order to not stimulate premature laying. This can either be a caged system or housed. They are then transferred to a layer facility between 18 and 20 weeks of age where they will be photo-stimulated to begin laying eggs. Day lengths are artificially controlled in the majority of commercial flocks (caged is the most common system in order to achieve this control), and the chickens are fed rations high in calcium and adequate in protein needed to support their elevated laying numbers. Modern hens have been selectively bred to produce many more eggs than they naturally would, above 250 a year with some reaching 300 a year. This compares to less than 30 per year in wild fowl, and 150 per year for hens in the early 1900′s.

Layers are forced through egg-laying cycles in which they lay for just over a year, are forced to rest or molt for a few weeks, and begin a new cycle. Each cycle results in less eggs and lower quality as the hen’s ability to support the continuous laying decreases (despite constant supplementary feed), and layers are usually slaughtered after anywhere from 1 to 3 cycles depending on their productivity. Molting is induced by drastically reducing their food intake and also reducing daylight hours to halt reproductive function. Molting is done to enforce a “rest and recovery” period to prolong the productivity of the layer as much as possible.

Mortality in laying flocks can be put down to cannibalism, disease, environmental extremities in uncontrolled facilities, and general ill health due to the intensity of production. Rates can be anywhere between 12-18% in caged systems and 35% in barn systems. Mortality is often highest in free-roaming housed systems where de-beaking is not performed and the birds are allowed to interact freely with each other. Cannibalism is often thought to be a sign of poor welfare, and is seen regularly in systems where birds are over-crowded, poorly managed, not provided with enrichment, and are not allowed to perform natural behaviours.

Approximately 6.6. billion chickens make up the egg-laying industry per annum, with the average commercial hen being slaughtered anywhere from 1.5 to 3 years (their normal lifespan being 6-12 years) as their egg production begins to decrease from around 30 weeks. 

Point: Fowl typhoid immunization is a vital supplement to cultivate cleanliness in decreasing antimicrobial obstruction brought about by broad prophylaxis of anti-microbials in poultry. This study was embraced to foster an immunization up-and-comer from a harmful strain by plasmid-restoring.

Spot and Duration of Study: The examination was completed in the Department of Pharmaceutical Microbiology and Biotechnology, University of Nigeria Nsukka, for a long time.

Strategy: Multi day-old pullets were isolated into three gatherings of ten birds each. This contained a negative benchmark group (unvaccinated) (NEG), a live SG9R immunization positive gathering (SG9R), and a nalidixic corrosive safe plasmid-relieved 85-kb plasmid Salmonella gallinarum (NAR). Plasmid restoring of the harmful strain was finished by hatching in sodium dodecyl sulfate (SDS) and loss of the 85-kb plasmid was not entirely settled on agarose gel electrophoresis. Inoculation was done subcutaneously at 4 and 7 weeks old enough, trailed by challenge with the harmful S. gallinarum. IgG was estimated utilizing Enzyme-connected Immunosorbent Assay (ELISA). The versatility of the SDS-relieved nalidixic corrosive safe 85kb plasmid Salmonella gallinarum insusceptibility was exhibited by inoculating layer birds and contrasting the humoral resistance and that of a business fowl typhoid immunization (SG9R).

Results: There were higher IgG levels in the NAR bunch than the SG9R bunch. Security was over 70 % in the immunized gatherings.

End: The result of this current review shows that inoculation with suitable cells of sodium dodecyl sulfate-restored nalidixic corrosive safe 85-kb plasmid Salmonella gallinarum (NAR) gave layer birds defensive humoral resistance against ensuing test with the parent destructive strain containing the 85-kb plasmid.