Poultry health and disease
Generally, free-range poultry that is well cared for in a suitable yard has a very good quality of life. So much so that some hens in well-managed backyard flocks have been known to reach 10 years of age. But naturally, hens don’t live much beyond 3 years, even if they are allowed to!
If you keep poultry and you want to make money from them, you have to accept that their most productive years in terms of egg and meat production are the first three. Beyond that, it is generally not economic to keep them unless, of course, the birds are valuable breeding stock or of particular sentimental value. Keeping unhealthy birds alive can mean that they contaminate the environment for healthy birds. It is generally best to euthanase them and replace them with young healthy birds.
How to Prevent Disease in Poultry
The best way to avoid disease in your birds is to look after them well. This means:
a well-balanced diet
fresh water
good hygiene
and a comfortable, safe, and stress-free environment.
In intensive systems, the birds are often under chronic stress, which makes them more likely to pick up infections, and the over-crowding can mean that microbes build up in the environment. To prevent disease, there is a widespread use of vaccinations and in-feed medication. This shouldn’t be necessary for backyard flocks.
Poultry Hygiene and Sanitation
It’s important to keep the poultry houses and yards clean. Birds pick up infections when microbes build up in the environment, as when excreta builds up in the poultry house and the runs get muddy.
Cleaning the poultry house is always laborious and it takes time, and it has to be done correctly to get the best results. It involves de-stocking, then cleaning and disinfecting nest boxes and perches as well as floors and walls. Thorough removal of all waste is very important. Disinfectants will not work on top of dirt because they may not be able to penetrate it.
Sunlight is a good natural way to kill microbes. Earth floors can be disinfected using a phenolic solution, preferably diluted in oil and there are chemicals to kill parasite eggs. Fumigants can be used to kill microbes and insects.
Quarantine New Poultry Before Introduction
There is a risk of bringing in disease when you introduce birds that are sick, or that look healthy but are incubating the disease. Make sure any bird you introduce appears healthy, and pen it separately for a while before gradually introducing it to the flock. This helps ensure it isn’t incubating any nasty diseases, and the procedure has the advantage of giving both new and resident birds time to get acquainted safely.
Recognising Signs of Illness in Poultry
It is important to be able to detect the very first signs of illness so that affected birds can be removed for treatment or euthanasia. The signs to look for are:
dullness
drop in appetite or loss of appetite
feathers fluffed up
sitting on the floor, reluctant to move
diarrhoea, possibly even blood-stained
soiled feathers around the vent
lameness
a hanging wing or wings
rapid wheezy or difficult breathing, perhaps even open-mouthed breathing
a discharge from any orifice (nostril, eye, beak, cloaca [vent])
reddened skin and/or feather loss
swelling of the face and/or wattles
Infectious Diseases in Poultry
In good free-range systems, there is little stress and the birds are well-fed, comfortable, and clean, and infectious diseases should not be a problem. However, sometimes free-range birds are at risk of parasite diseases especially if they have been introduced from an intensive system where they haven’t had a chance to develop natural immunity. For a few weeks after they’ve been introduced, it’s wise to give these birds medicated feed to prevent coccidiosis, and anthelmintics to treat worm infections. This will help them adapt safely to their new life.
The microbes that cause disease can be classified (from smallest to largest) as viruses, bacteria, fungi, protozoa, and parasites. Bacterial diseases can often be treated with antibiotics, and the diseases caused by protozoa, fungi, and parasites can usually be treated with specific medication. There is generally no effective treatment for viral diseases, but there are vaccines available to prevent some of them.
Nutritional Deficiencies and Other Poultry Health Issues
An imbalance in nutrients in the feed can cause disease. For example, calcium deficiency and phosphorus deficiency can result in poor egg-shell quality, and zinc deficiency can result in poor feathering. As discussed in Part 5, it is important to provide a balanced ration.
Poisoning can result in a wide range of clinical signs. Common poisons include rat and other vermin poisons, old paint containing lead, and some poisonous plants.
Keeping Health Records for Your Poultry Flock
It’s good practice to keep an accurate record of all instances of illness and death in your birds and to note what vaccines and medications were given and when. Record the birds involved, and what they were given including the product lot number and the outcome. The records will be useful for future reference.
Learn More About Poultry Health
Looking after your poultry well is the best way to prevent disease. If you're new to chickens or want to sharpen your management skills, our online poultry course covers everything you need to know to get the best from your flock.
Next in series: Common health problems in poultry
