Dr Lily Ngullie
ACTO (Animal Science) KVK Longleng
Layers are sexually mature female birds producing eggs. The laying starts at 20 weeks of age, egg production is high and economical up to 72 to 75 weeks of age, after which the decline begins. When the egg production goes below the economical level or the “break-even point”, the birds are culled. At 18 weeks of age all under grown pullets are to be culled and disposed off. Careful selection at the time of housing enables better returns and fewer culls later. The stock can either be reared in the same house where it was grown or transferred to laying house. Although the trend has been towards housing commercial layer strains in cages, there are still a good percentage of commercial layers kept on floor, slat or wire. The laying period, also called as the laying cycle, or biological year is when the birds reach 5% egg production on a hen-day basis and continues to the end of the bird’s laying cycle and the birds are sold as “spent hens”. One of the most profitable ways is to follow “all-in, all-out” practice. This simple means that the farm has only one age-group of birds. It helps in disease control within the flock. With decreased stress from disease and reduced mortality, rate of laying is higher. Over and above these, birds of one age group greatly simplify the management. Placing of laying nests: Nest-boxes should be placed at least one month before the start of laying in order to encourage the birds to lay eggs in the boxes. Multi-tiered egg boxes can be used for chickens.
Housing:
Laying cages: the use of laying cages for commercial egg production has become exceptionally popular. The wire floor should be extended past the front of the cage for 38 cm and rounded so as to collect the eggs there. The floor of the cage should be about one meter higher than the ground level. In order to collect the droppings from the cages a shallow pit at a depth of 30 cm from the ground level and length wise just under the cages maybe constructed. Long, continuous troughs are used for drinking water and feeding caged layers. Some of the advantages are easier culling, less problem due to parasites and other diseases, housing of more number of birds in limited space, clean egg production etc. Some of the disadvantages include high initial investment, wet litter, odour and fly problem.
Deep litter system: Layers on deep litter must be provided with nests. There are different types of nests. The single-compartment nests, where one nest is provided for 5 pullets. Sufficient nests will aid in the prevention of floor eggs. The community nests are of dimensions of 2 ft (0.6m) × 8 ft (2.4m) and should be provided for every 60 pullets.
Light in the layer house:
Light entering the eyes of birds induces response in the hypothalamus, which in turn, through releasing factors, affects the rate of secretion of gonadotropic hormones from the anterior pituitary gland. The gonadotropic hormones affect the activity of gonads and, in turn, the reproductive behaviour of birds. Age of sexual maturity and rate of egg production are affected by pattern of lighting in the laying house but this does not have the power to either stop or start these reproductive processes.
Use correct lighting schedule to ensure better performance: While light period should not be increased for growing birds, it would be to the advantage to increase the light period or photoperiod for laying chicken from 22nd week of age onwards at the rate of 15 to 30 minutes per week so as to reach 16 hours of total photoperiod (natural plus artificial) at 33 weeks of age. Never decrease light during laying period. When the birds have been in lay for about 6 months the photoperiod may be increased to 17 hours per day. The light period maybe constantly maintained throughout the rest of laying period.
Culling of non-layers and poor layers:
Non-layers and poor layers reduce the efficiency of flocks and often remain continuous source of problems. The birds should be held in natural position while examining. The bird’s body should rest comfortably on the palm of left hand, leaving right hand free for examination and handling. It is often necessary to separate and cull out the poor layers from the flock. The birds that have laid well for short period but have stopped laying for some reason or other should be culled out. There are four important characters which should be considered to distinguish good and poor layers:
a) Condition of birds- the healthy birds are vigorous, well fleshed but not fatty, tight feathered with tail and wings carried well up, expression bright and alert.
b) Moulting- it is a natural physiological process for the birds to renew old feathers at the end of the first year of laying. The time and duration of the first annual moulting are important points in distinguishing the poor and good layers. During moulting process, the feathers on different parts of the body are shed in the following order: head, neck, breast, body, wings and tail. Early moulters are usually poor layers. Such birds start moulting early and take unusually long time (24 weeks or so) to complete moulting. Often they stop during the moulting period.
c) Depigmentation: there is an abundance of yellow pigments in the different body parts of pullets. This is due to the deposition of carotenoid pigment, mainly xanthophylls coming from the feed. As the pullets come in egg production, these pigments are transferred from the body to eggs and slowly the body parts start bleaching. The depigmentation of body parts follow a particular pattern depending upon the blood circulation in those parts. Thus, bleaching of the body, to a certain extent indicates the egg laying capacity of layers.
Sexual maturity:
Early maturity and egg production are shown to be positively correlated, i.e., birds that mature early turn out to be good layers.
Feeding:
A good quality layer mash with BIS specifications should be provided to the laying birds. The feed maybe given in linear feed troughs or in hanging feeders. Provide 5 hanging feeders, each 50 cm in diameter with 20-25kg capacity for 100 layers. Place the feeders within 3 meters of waterer. Stir the feed few times a day to promote eating. Water space of 2.5 linear cm per bird should be provided. Increasing watering space 25% when temperature goes above 27°C. The feeders in the laying pen must be positioned in such a way that the upper edge is slightly higher than back of the birds. The feeder should not be filled more than 1/3 full.
Restricted feeding: the weight of the birds has to be controlled to prevent fat accumulation in birds so as to get better egg production and a high percentage of fertility, also to reduce laying mortality. The normal restricted feeding schedule is by quantity restriction i.e. providing 70-75 % of ad libitum feeding from 9 to 22 weeks and 90 % of ad libitum during the laying period or through skip-a-day feeding.
Advantages of feed restriction
• Uniformity in the folk
• Produces better egg size during early periods of laying
• Reduces body weight at sexual maturity
• Offers better livability during production
• Reduces problems of fertility and hatchability
• Leg disorders due to over feeding can be controlled
• Mortality due to over feeding will be prevented
• Reduces mating difficulties due to large body size in males
