When there is a drop in egg yield in a farm, one or more of the following factors must be responsible:
Disease setting in
Worms in the intestines
Ectoparasites on the body won’t let them settle down to feed enough.
Birds not drinking enough water
Feed not adequately balanced
Birds not taking enough ration (perhaps due to overfeeding with green vegetables)
Birds under-going moulting of feathers
Sudden change in ration
Birds under treatment with some classes of drugs known to drop production (e.g. the Sulphonamides)
Birds recently vaccinated, and under-going vaccination
reaction.
Birds recently moved from their old place to a new place
Bad laying season of the year (usually June to August)
Birds frightened by strange noise or sight.
Let us briefly deal with how these factors cause reductions in egg production.
Several diseases are known to cause drop in egg production. Some of them achieve this by inducing anorexia (lack of appetite). Others achieve this by elevating the body temperature and leading to increased loss of calories, while others still achieve this by parlay sing or reducing the efficiency of the egg-making processes or machinery. A disease like Newcastle can completely stop egg production due to the harmful effect of the causative viral agents on nervous control of the egg-making organs.
Intestinal worms compete with the blood capillaries of the intestine for the feed eaten by the fowl. While the digested feed is supposed to be assimilated through these capillaries and taken to the ovary and oviduct for the processes of egg-making, intestinal worms absorb some of these digested food thus reducing the quantity going for egg making. The tape-worms and large round worms are worse culprits here.
Ectoparasites (parasites found on the body) like lice, fleas, mites, disturb the feeding of the fowls as well as suck blood out of them. Much feeding time is spent in scratching with their beaks all over the body as the insects disturb them. Some of the blood which would have gone into supplying the needed ingredients for egg making is lost to the insects which feed on the tiny skin capillaries.
With broody hens isolated to hatch fertilized eggs for small-hold or backyard poultry-keeping, the ectoparasites just won’t let them sit for a few minutes on the eggs, so that such eggs have little chance of hatching. (Broody hens are priced asset to small-hold farmers who cannot afford the cost of even the smallest incubator)
Water forms more than 80% of the egg. so, if enough water is not fed to layers, egg production becomes adversely affected’
If the feed is lacking in some ingredients essential for egg-making, production drops, some of these ingredients affect production more than others. For instance, a flock fed much less than 15% crude protein is bound to suffer serious drop in production. Similarly, low levels of Thiamine. riboflavin, pyridoxine pantothenic acid or any member of the V.P Matthill group could adversely affect food digestibility and assimilability leading to reduced egg yield;.
Poor ingestion of ration may be due to feeding higher than 2% green vegetables, or due to mouth lesions like wet-pox or due to unpalatability of ration caused by bitter drugs added to feed), or improperly constituted ration.
When birds are under-going moulting, there is usually a drop in egg production, but as soon as the moulting is over less food now goes into supplying nutrients to feathers. Consequently a good deal of the ration goes into egg production and production increases.
There is a claim in certain quarters that egg production could be stepped up by artificially inducing molting in a flock by starving it of water for about three weeks. During this period birds are fed 25-40% of their usual water requirement: (Lower percentage is fed in the wet season). When molting subsides, the birds are again restored to normal water intake. Egg production is claimed to be very highly stepped up thereafter. (This author has not carried out sufficient investigation and research into this claim to be able to come out with his concrete findings and opinion on this.
Sudden change in type of ration has been known to constitute stress to layers sufficient to drop egg production. It is therefore recommended good husbandry practice to adopt a piece-meal approach towards any need for a change in ration source. This piece-meal or gradual change is spread out over a period of seven days. The table below shows the recommended pattern of change.
Certain drugs are known to adversely affect egg production. Consequently use of such drugs are restricted to growers and cockerels. Where however such drugs are the only available ones, for application to layers, drop in production should therefore not come as a surprise. Many sulphonamides are known to cause such drops.
Recently vaccinated layers drop in egg production. During the vaccination reaction the weakened microorganisms introduced into the body soon start to cause mild form of the disease which they have been created to cause. In the process the host develops antibodies and consequently becomes immune. Some of the symptoms of the disease caused may include lack of appetite, fever, mild cough, etc. During the period when these symptoms are shown, the flock is said to be undergoing vaccination reaction, and they often drop in production until the period is over. It usually does not last more than a few days.
Movement of birds constitutes a stress factor which adversely affect egg yield. More energy is lost and this must be replaced first before the egg factory could receive its quota of ration. Consequently, the flock spends the next day’s ration in replacing energy drawn from the energy store houses in the birds and this leads to low production. Another factor here is psychological.
Finding themselves in a new and strange environment, all attention is focused on the defense-system of the bird filled with fear and apprehension or why they have been brought to the new place, the whole nerves are alert and like a city gripped with fear of an impending attack there is reduced production and this goes on awhile until the tensed-up nerves become relaxed once more and the fear gone. At this time, normal egg production is restored.
Some seasons of the year are known as bad laying seasons, and as such egg production is expected to drop. The best laying season runs from September to April or May. It is therefore better to order chicks so that they arrive by March or April. This will enable them to commence laying during the good laying season. If chicks were hatched, say in July, they would start to lay by the month of January. This leaves them with only about 2-3 months of the good season. As soon as the rains come, their production drops, and by the time the next good laying season shows up in September or October, they shall have passed over their pullet year
| Days | Old Ration | New Ration |
| 1st day | 90% | 10% |
| 2nd” | 80% | 20% |
| 3rd “ | 60% | 40% |
| 4th “ | 50% | 50% |
| 5th ‘” | 40% | 60% |
| 6th “ | 20% | 80% |
| 7th “ | 10% | 90% |
| 8th | 0% | 100% |
and consequently age would be against their giving a good production like their yet-pullet counterparts. Thus the over-all profit derived from such, a flock is much lower than that from those hatched in March or April.( 13) Strange noise like those of newly installed engines in the vicinity, noise of other animals, loud horns of vehicles etc. can reduce production if such noise keeps coming on and off, However if it continues, the birds later get used to it after some days or weeks, and normal production returns. Similarly, strange objects or strange activities can instill fear in the flock and lower production for that particular day. By the next day or so, they get used to seeing it and realizes that there is no danger inherent in such sight, thus restoring normal production.