Effective Strategies for Controlling Chicken Disease Outbreaks
A common practice among farmers in the control of chicken disease outbreaks is to isolate all the sick ones in a separate pen away from the pen, housing the rest of the flock. This practice is good and helps to control the death rate to an appreciable degree.
Isolation and Observation: Early Detection and Treatment
However, recent research carried out on the best ways of controlling chicken disease outbreaks has revealed that a much higher percentage of the flock could be saved from possible deaths from outbreaks if the following measures are adopted.
Maximizing Disease Control: Proactive Measures for Flock Health
I. When the disease is discovered early enough and only a few birds have been affected, the affected birds are removed from the flock to an isolation pen which must be far away from the rest of the flock. Next, a close observation lasting for several hours is conducted on the flock with a view to spotting all those who are just beginning to show symptoms of the chicken disease.
The appropriate treatment is then given to the rest of the flock with a view to arresting further incubation of the disease in those yet-to-manifest symptoms, as well as preventing others not yet affected from contracting the chicken disease before the causative organisms are flushed out of the body. The already sick ones in the isolation pen are then very closely treated; with very weak ones’ receiving individual treatment. This approach is in line with the practice commonly adopted by farmers. It is best applied only if the outbreak is yet starting and only a few birds have been involved. The other line of approach is adopted when many birds are already affected.
Ventilation and Treatment: Managing Disease Outbreaks with Improved Airflow
2. When a high percentage of the flock has been affected (i.e. where 30% or more are sick) it is no longer advisable to remove the sick birds as in the above case, neither is it of much use treating all the flock together in that pen. Measures to adopt here are of two types;
Type One:
Contaminated Litter: Addressing the Challenges of Disease Transmission
If the symptoms of the chicken disease do not include any affection of the gastrointestinal tract i.e. there is no change in the faecal droppings of the affected birds, and things like diarrhoea, the whitish, greenish or reddish colouring of faeces are absent), then it is to be assumed that there is not much contamination of the litter with the causative organisms. Here, the birds may be shedding the organism into the air by respiration. Even if there are nasal or ocular discharges (i.e. discharges from the nose or eyes), those may not be enough to seriously contaminate the litter.
Related: How to Care for Layers in Chicken Farming
High Infection Rates: Dealing with Disease Outbreaks in a Large Flock
In chicken diseases of this nature, efforts are geared towards improving the ventilation in the house, so that contaminated air is not held up inside the house for long periods. This improved circulation of air is coupled with’ intensive treatment of the entire flock. This is a recommended measure to adopt and will be of much help in controlling such outbreaks. To reduce the chances of the birds being re-infected or increasingly infected by germs contained in the nasal or ocular droppings, including any that may be latent in the apparently normal faecal dropping, a one-inch deep fresh litter is spread on top of the old litter in the house. The best still, is to change the entire litter if the farmer can afford the cost.
Type two:
Breaking the Cycle: Severe Contact Between Birds and Contaminated Litter
Where the chicken disease is accompanied by diarrhoea, or visible change in the texture of the faeces or where nasal or ocular discharges are more profuse, it is to be expected that the litter here should be very highly contaminated by the causative organism. Birds kept in such a house and being treated there continue to pick up fresh organisms from the litter as long as they remain in that house. The result is that as the drug being given tries to kill the organisms in the birds, the birds themselves continue to pick up more organisms discharged on the litter via faeces or nasal droppings, and the cycle continues unbroken. In this case, even if the sick ones are removed to an isolation pen, the faeces they dropped on the litter before they were isolated still contain the infective agent and any healthy birds in that pen become infected with the chicken disease each time they pick on the litter. It is therefore easy to see that the safest way to control this type, of outbreak is to severe or break any contact between the birds and the contaminated litter. This can only be achieved by either (I) Removing all the healthy birds from that house or (2) Removing all the litter in that house. The choice is that of the farmer. Before making the choice the farmer is expected to look at his labour force, as well as the size of the fallow pen or isolation pen in his farm. If he has enough free pen to accommodate the birds, he removes all healthy-looking birds into this clean well-littered pen and a few days of drug medication may quickly put a stop to any threat of the outbreak. At the same time, those already showing symptoms are removed to a smaller healthy pen where they are closely attended to. Those too affected to be saved, are removed and destroyed. When treatment has restored apparent health to the few sick ones, they are sent to the market for meat, It is very difficult for any bird that has been saved from death during an outbreak to lay as many eggs as it would have done. It is therefore wise husbandry practice to sell for meat any such birds, as they are often kept at a loss as egg producers. The amount of eggs they can lay may sometimes not cover the cost of feeding them. But if they are sold for meat, they will usually give back enough money to cover much of what has been spent so far in keeping them. (Your local veterinarian will advise you on whether your case deserves this raise-for-meat-only kind of treatment, as not all chicken diseases in a flock call for this.)
Practical Considerations: Removing Healthy Birds or Changing Litter?
If on the other hand, it is considered better to remove the litter because of the unavailability of a house to hold the birds, the house should be cleaned out in the morning and fresh litter replaced the same day. While this is being done the birds may be let out of the house into a secured run. Where there is no space outside safe enough for that, the birds may be left inside the house and the house partitioned into two for the purpose. While one half is being cleaned and refilled with fresh litter, the birds are crowded in the other half. Later, they are crowded in the cleaned half, while the other half is being cleaned and littered. When completed, the partition is removed to allow the birds their former freedom, This whole exercise must be completed within a few hours in order not to keep them crowded in half the house for the whole day.
Saving the Flock: Intensive Treatment and Timely Actions
Even if there is no space to isolate the very sick ones in, they are more effectively treated when the chances of picking up more germs from the contaminated litter are reduced. However, wherever possible, it is best to isolate very sick ones in a separate pen.
Post-Outbreak Measures: Disinfection and Preventing Re-Infection
The whole idea behind the above measures is to attempt to prevent unaffected birds in the flock from ever becoming infected by the already affected ones. This is because those not affected will continue to produce well, while those affected but later treated will never produce well again if they are layers.
The treatment given to them is only aimed at enabling the farmer to sell them as meat and recover some of what he has spent on them.
As earlier pointed out, not all chicken diseases permanently destroy the chances of affected birds to produce profitably. chicken diseases which are known to cause such permanent damage include Newcastle (virulent strains), Leucosis or Marek’s disease, Infectious Nephrosis or Gumboro disease, Tuberculosis (treatment here is, however, uneconomical and illegal), Ulcerative enteritis, Infectious hepatitis, encephalomyelitis, Reticuloendotheliosis, Myelocytomatosis (orChloroma), and a few others.
Safeguarding the Farm: Cleaning and Disinfection of Equipment and Facilities
After an outbreak of a chicken disease has been controlled in the affected flock by the application of measures enumerated above, the next stage is to ensure that the entire farm is kept safe from possible re-infection. This is achieved by washing and disinfecting all, equipment being used including waterers, feeders, wheel-barrows, pails, pans, boots, shovels etc. Next is the disinfection of all houses, pens, feed stores, egg stores, and ground surfaces inside the farm, especially around the pens and other houses on the farm.
Recovery and Prevention: Anti-Stress Treatment and Fallow Period
For four weeks after controlling the outbreak, the entire flock is treated with any anti-stress drug, rich in vitamins (especially the B-complex vitamins). If the pen was evacuated of birds such a pen must remain fallow and should not be re-stocked with birds for the next three months. During the very dry season, this period could be reduced to two months. It should be noted that before leaving a pen fallow, such a pen should first be thoroughly washed and disinfected with strong disinfectant.