Choice of Production System: Three main systems are used in the layer business; battery cages, deep litter and range. Each of these has its merits and demerits but the range system is the least common for large-scale producers probably due to its high demand on land, supervisory labour and security. The battery system requires an initial large capital outlay but involves much less labour in replacement of litter and has a much lower level of parasite build-up and disease risk. This is the system that this paper focuses on.Feed: The question of whether an egg producer should mix his own feeds or rely on commercial feeds depends on the size of operation and on the skill available to him. For production levels below 2,000 layers, a farmer can conveniently rely on commercial feeds, but for production levels beyond that, he may find it more economical in terms of labour utilization to produce his own feeds. For a farmer who wishes to buy feeds, here are a few hints to help him estimate his feed requirements and financial outlay. For layers: Allow about 50 tons per 1,000 layers for the whole laying life of 455 days. Note that when a laying flock is changed from one feed to another, there is usually a slight drop in egg production for a short period irrespective of the quality of the second feed. This is due to adjustment of intake for the new feed.Records: The value of keeping accurate, up-to-date records in a large poultry farm cannot be overstressed. Practically, all decisions to be made on culling, management adjustments, choice of breed, use of medication, change of feed etc., depend on accurate records. Without them, a farmer would be operating his business like a person going through a crowded market blind-folded. His cash losses and disease outbreak will take him unawares. Records should be kept for every section of production. In the layer unit such records as:
-Number of Eggs produced.
-Number of layers to date.
-Egg production percent.
-Average feed consumption per layer per day.
-Average water consumption per layer per day.
-Date of hatch.
-Number and percentage of cracked or malformed eggs are essential.
These data can be summarised per month and recorded in a separate chart for adequate guidance. A monthly egg production (%) will indicate what season, breed or age of chick gives the peak production. Feed consumption and water consumption warn him of heat stress when the former decreases and the latter increases sharply. Morbidity warns him of disease incidence and the need for prophylaxis.
The Egg: The egg is both the origin and the end product of poultry production. The fertile egg which is capable of incubation and hatching is obviously the origin of a new generation of chickens, while the table egg which ends up in the breakfast table can be regarded as an end-product. Thus, the famous poser, on whether the egg is the mother of the chicken or, vice versa refers to a fertile egg. In this discussion, we are interested only in the table egg which is produced by housing laying hens without any cocks to mate them. It should be emphasized here that the presence of the cocks is totally irrelevant and undesirable in the production of table eggs. This is because fertilized eggs apart from being more expensive to produce than table eggs are also liable to early deterioration especially under temperatures above 12ºC or 80ºF, because of the development of the embryo. Such eggs are discriminated against in the egg market.
At the time it is laid the egg possesses its highest food value. Also because of the uneven distribution of its chemical constituents, the egg is subject to changes that diminish its original food value. These changes are mostly affected by factors of the external environment and time. The need to process eggs is therefore obvious – to preserve the original food value for as long as is possible
Food Value of the Egg: A typical egg contains about 65% moisture, 12% protein, 11% ash, 11% fat and 1% of carbohydrates. It can be seen that apart from moisture, protein is the richest nutrient of the egg. On moisture-free basis, one egg contains about 35% protein. This protein is very rich in essential amino acids which are highly desirable in diets of humans and other animals. The food value of the egg is therefore enormous, especially in developing countries of the world which invariably, lie within the tropics.
The egg is reasonably protected from adverse environment and spoilage through its shell and membranes. Loss of moisture through the shell pores is retarded by means of the cuticle. The invasion of micro-organism is also prevented by the cuticle, while the albumen contains protein which can fight the putrefaction bacteria and retard spoilage by putrefaction. The effectiveness of these defense mechanisms is of course limited by time and degree of contamination. Beyond a certain period of exposure to adverse environment, the egg will eventually succumb to microbial and other sources of spoilage.
Change in Egg Quality: The egg is considered fresh immediately it is laid. Quality changes occur during storage and reduce the taste and food value of the fresh egg accordingly. The main objectives of processing are to retain the food value and quality as much as possible and to prolong the period the egg can be utilized while in acceptable state of freshness and quality.
Egg Processing and Preservation: One of the simplest methods of prolonging the edible life of an egg is to ensure that it is not contaminated by chicken faeces or other dirt. Layers kept in deep little system have a high incidence of contaminated eggs especially where adequate numbers of laying boxes are not provided. In this case, the layers may drop the eggs on the floor and spread dirt and faeces over them. This is one of the advantages of using battery cages for layers. The commonest methods of preserving eggs involve chilling, treatment with chemicals and dehydration. Some techniques may involve a combination of these methods. Eggs stored in cold chambers can keep for 2 – 3 months.