Introduction
This manual covers the steps aviculturists can take to reduce the risk of disease spreading through their own aviaries. It is important that birdkeepers are aware of the concept of a “closed aviary”. That is, they consider the try to keep their own collection of birds as separate as possible from outside sources of infection. These may be new birds entering the aviary, wild birds dropping faeces and feathers into an aviary or a show bird returning to the aviary after having been infected. The recommendations in this document are designed to help reduce the risk of disease entering the aviary and contains standard management practices that will reduce the multiplication and spread of any disease that does gain entry. These guidelines can be applied to any species of animal in captivity.
Hygiene
The most effective method of preventing the spread and multiplication of disease causing organisms is to maintain clean aviaries. It is impossible to completely sterilise a working aviary of all bacteria, fungi and viruses. However, good management can keep the level of contamination with these organisms low. The argument that birds kept in clean aviaries have poorer immunity is completely false.
Cleaning and disinfection
The best method of reducing levels of infectious organisms is to clean all surfaces with soapy water. Detergents help shift the organic waste that comes from keeping birds, such as food, faeces, and feathers. It is important to design aviaries to ease your ability to clean with minimal disturbance to the birds. Disinfection should follow cleaning and is the application of a chemical that will kill remaining disease causing organisms. Most disinfectants will not work in the presence of organic matter so cleaning first is essential. Some disinfectants can be irritant to birds skin so use only at recommended dilutions and where possible rinse afterwards.
All food and water bowls should be made of a material that is smooth and hardy such as stainless steel, glass or glazed ceramic. Plastic dishes develop small cracks as they get older and make effective cleaning difficult. All food and water bowls should be cleaned daily and disinfected weekly.
Where possible aviary floors and perches should be cleaned weekly and disinfected monthly. During the breeding season this may not be possible because of disturbance to birds risking breeding success. Some species are more tolerant than others, and if a regular routine is followed most birds will adapt to it.
Nestboxes should be thoroughly cleaned and disinfected between seasons. If possible cleaning and disinfecting between clutches is recommended. Fresh nesting material should be added after each cleaning.
Flooring
The floor of the aviary can have a tremendous impact on the build up of disease causing organisms. Dirt or sand floor aviaries gradually accumulate high levels of bacteria, fungi, viruses and parasite eggs. Birds that forage on the ground, especially after spilled food, will be exposed. If using dirt floors, or planted aviaries, the top several inches of soil should be removed and replaced annually. Raking the soil does not get rid of the organisms. Treating the soil with lime and other chemicals is also mostly ineffective. To reduce the spillage of food material onto the aviary floor a feeding shelf that allows food to fall outside the aviary can be used. This will also reduce problems with rodents.
Concrete floors are better as they can be easily cleaned and disinfected. They should be sloped to provide drainage out of the aviary. Some breeders like to cover the concrete with a layer of sand. If using this method, the sand should be replaced regularly.
Suspended aviaries that allow faeces and food material to fall away from the birds are useful. However the bottom wire floor often needs cleaning and disinfecting to prevent faeces caking it up.
Breeding boxes and cages for small birds should have newspaper laid on the cage floor which is replaced at least weekly.
Movement of waste material
Leaving food and faeces to accumulate, whether in or out of the aviary encourages rodents and aids in the multiplication of disease causing organisms. All waste material should be collected regularly and disposed of in accordance with local council regulations.
Recycling of seed is only recommended if it is kept separate for each aviary. There is a strong possibility of spreading infectious disease in the seed if it is all collected, recycled and then re-distributed between aviaries.
The movement of waste water from cleaning should not flow between or through other aviaries. All waste water from cleaning should be disposed of as sewage according to local council regulations.
Separation of groups of birds
A useful management technique with large numbers of birds is to manage them as groups of separated aviaries. This means that cleaning equipment, feed and water bowls, nets and other equipment are assigned to a particular aviary and stay only with those birds. This reduces the risk of transferring infections between groups of birds on equipment. This management practice is also useful in case of a disease outbreak as particular groups can be more easily isolated. Often the groupings follow the birds’ role in the aviaries. Examples of this include: show birds and breeding stock; adult birds from juveniles; for pigeons, racing birds and breeding stock; or in a zoo collection, display birds and breeding animals.
If this practice is to be useful, birds must be physically separated from other groups. In indoor situations this means separate rooms and air spaces as many diseases (such as Chlamydiosis) can spread in aerosol droplets.
Exclusion of wild birds
Collections of birds will inevitably draw wild birds to the vicinity. This is particularly so if waste food is not collected and disposed. Aviaries should be designed to exclude wild birds. This has been highlighted in New Zealand with the Salmonella outbreak in wild sparrows. There have been many deaths of aviary birds with the strain of Salmonella (DT 150) carried by the sparrows. Techniques for excluding birds from aviaries include the use of fine mesh wire (sometimes as double wiring), solid roofed aviaries and the use of indoor facilities. The use of these techniques should be tempered by the need of most birds for exposure to direct sunlight. Direct sunlight also aids drying and inhibits fungal growth in aviaries. No wild birds should ever be placed in the aviary deliberately.
Quarantine facilities and management
The role of quarantine
Quarantine is used to allow the detection of unhealthy birds entering the collection. All new birds and birds re-entering the collection (eg from shows) should go through quarantine. The amount of diagnostic testing that occurs in quarantine varies between facilities but the chief strength of using quarantine is that it gives you time to detect a bird’s illness. A bird that looks unwell should never be added to the collection. There are lots of examples of birdkeepers who have placed a new bird directly into their collection, introduced a new disease and had most or all of their birds die.
The time that birds remain in quarantine varies with the value of the collection and the relative disease risk. For example a bird purchased at a pet shop for introduction into a valuable breeding collection should spend a long time in quarantine. While that bird has been in the pet shop it has been exposed to birds from many aviaries, any of which may be carrying an infectious disease. On the other hand if you purchase a bird from a breeder you know well and who has a clean aviary with no history of recent disease you may decide the disease risk is low and therefore reduce the quarantine period.
A recommended quarantine period to cover most disease incubation periods is 30 days. In most cases if birds have been infected with disease they will show signs of illness in that time. Birdkeepers should pay close attention to the attitude, appetite and droppings of birds in quarantine. Any suspicion of ill health should result in either an extended quarantine or denying the bird entry into the collection.
Sentinel birds
Some birds will recover from an illness and look healthy but still be carrying infectious organisms. These “carrier birds” are difficult to detect using routine quarantine but can bring devastating illness to your collection. Your ability to detect these birds can be improved by putting a low value bird from your collection in with the quarantined birds and leaving it there for one to two weeks. If this bird develops disease your new birds may be carriers and should not be admitted to the collection.
Birds should be moved in and out of quarantine in batches. There is no point in releasing birds from quarantine if they have just been exposed to new birds arriving.
Quarantine facilities and placement
The area that you place your quarantine facilities should be physically separated from the rest of your collection. All feed and water bowls, cleaning equipment and nets should only be used in the quarantine area and not in other aviaries. Separate areas for cleaning and food storage should be part of the facility. The quarantine area will be separate from your hospital cages for sick birds.
Having overalls and gumboots that are only worn in the quarantine facility will limit the chances of carrying infectious disease out on your clothing or boots. Footbaths are generally ineffective unless boots are physically scrubbed clean and the disinfectant in footbaths is changed at least every day.
Movement of birds in the aviary
Introduction of new birds
All birds newly arrived to the aviary should be taken directly to the quarantine facility, and remain there until judged as fit to enter the main facility.
Moving existing birds
If you are moving birds between groups, keep careful records of who was moved and where they were moved. Good record keeping can greatly ease trying to track down birds that are suspected disease carriers. Moving birds between groups should be avoided wherever possible.
Show birds
Ideally show birds should be kept in separate facilities or aviaries to the breeding flock. In collections where the show birds are an important part of the breeding flock, keeping them in quarantine post-shows, or breeding them in separate cages is recommended.
Movement of people in the aviary
Owner/workers
Your daily round of the aviaries and rooms should move from the safest aviaries to those of highest disease risk. An order of movement for cleaning and feeding each day might be from stock and breeder aviaries; show or racing birds; juvenile birds; quarantine and finally hospital cages. Making sure hands and boots are washed between groups of birds is recommended.
Visitors
Visitors can act as a source of introduction of many diseases. Some breeders will therefore discourage visits from other bird breeders. As a courtesy when visiting another breeders’ aviaries you should make sure you have showered after dealing with your birds and put on clean clothes. Visitors should also be taken from low risk areas to high risk areas as detailed above.
Health Screening
Routine health checks
The amount of health testing recommended for an aviary depends on how isolated the aviary is from other birds, the design of the flooring and the previous health history of the flock. The commercial value of a flock may also influence the amount of testing done. A breeder who does not exhibit at shows, allows no visitors and practises good quarantine and hygiene will be able to carry out less health testing than a breeder who takes breeding birds to shows, has minimal quarantine and introduces new birds regularly.
The biggest problem with health testing is the number of diseases that can affect the birds for which there is no diagnostic test. With large flocks, individually testing all birds quickly becomes too expensive.
Some recommended health tests available in New Zealand include:
1. Physical exam
A complete examination of the bird can be a good tool in picking up early signs of illness. Birdkeepers should feel comfortable in handling their birds at least once a year. Weighing the birds and recording these weights is extremely valuable in assessing the health of a flock and also allows for greater accuracy in dosing birds with wormers and other medications. When examining the birds you should pay particular attention to faeces and urates, feather and muscle condition, the eyes, eyelids and nostrils and soles of the feet.
2. Faecal egg counts
Having a sample of the birds droppings checked is a good tool for picking up parasite eggs (tapeworms, roundworms and coccidia). This is especially important on dirt floors due to the high chance of re-infection. Resistance to common worming agents occurs in the parasites of all birds so it is important to check if you’re worming schedule is effective. Most veterinary clinics can provide this service or droppings can be sent via your local vet to veterinary diagnostic laboratories.
For a dirt floor aviary I would recommend this be done every 3 months. For concrete floor aviaries that are cleaned regularly twice a year testing is recommended and once yearly for suspended aviaries. See Appendix 1 for worming recommendations.
3. Chlamydia antigen testing
An important disease of parrots and pigeons is known as Chlamydiosis, Psittacosis and in humans, “parrot keepers fever”. See Appendix 2 for more information on this disease. Chlamydia testing involves taking a swab of the conjuntiva (eyelids) or cloaca of the birds and running a specialised antigen test. This test is best at detecting birds that are ill with Chlamydia and only has limited value as a screening test. If birds are showing conjunctivitis (weeping eyes) then they should be tested.
4. Psittacine circovirus PCR
Psittacine circovirus is a virus that causes the disease Psittacine Beak and Feather Disease (PBFD), and is one of the causes of “French Moult”. It affects nearly all parrot species (cockatiels seem to be very resistant). It is a highly infectious virus and very resistant in the environment. The virus can remain active for at least a year in feather dust and dried faeces. It causes nestling deaths, feather abnormalities and immune suppression resulting in secondary infections. No birds with feather abnormalities should be admitted to the aviaries without testing a feather for the virus. If an aviary is experiencing high numbers of nestling deaths amongst parrots then testing should be carried out on either nestlings or the parents of affected clutches.
Post mortems
Only a low percentage of adult deaths should occur annually within aviaries. It is important to get diagnostic post mortems done in any situation that involves large numbers of birds dying. Ideally, all dead birds should undergo post-mortem examination for disease surveillance within the aviary. However, if costs prohibit this all dead birds should be stored. The storage of bodies allows retrospective disease investigations should a problem be worse than originally anticipated.
If getting a post mortem done immediately, the bird should be taken to the veterinarian as found. If a delay of several hours will occur prior to shipping the body or during transportation, the body should be washed down with soapy water and then refrigerated. If maggots are present on the body it should be sprayed with an insecticide before chilling. Washing the body down first removes the insulating quality of the feathers and allows chilling of the body to occur more rapidly. This is important to delay post mortem decomposition. Refrigerated bodies will hold their value for post mortem for three to four days if kept cool. If it will be longer than three days before a body will make it to the diagnostic laboratory for post mortem then it should either frozen or fixed in buffered formalin.
Freezing is the simplest way to store a body long term and some diagnostic information can still be retrieved from a body stored this way. For small birds, the abdomen can be opened with scissors and the whole bird fixed in a solution of 10 % buffered formalin at a ratio of 10 times the volume of formalin solution to the size of the bird. This preserves the tissues in an excellent state for histology (microscopic examination of the tissues) but does not allow other diagnostic tests to be performed. Small jars of formalin solution can be purchased from your local veterinarian.
What to do in a disease outbreak
The previous notes cover routine procedures aimed at minimising the entry or spread of disease in an aviary. This section outlines procedures that will minimise the impact of a severe disease outbreak of it occurs on your property. In this situation you have responsibilities not only to your own birds but also to other birdkeepers. Do not be the one who spreads a disease to other peoples’ aviaries. An outbreak of disease is defined, for the purposes of these notes, as a sudden increase in the number of birds that become ill or die as a result of an infectious disease.
Movement restrictions
As soon as a birdkeeper suspects that there is a problem within the aviaries no birds should leave or enter the aviaries. This means keeping birds in quarantine until disease is resolved in the main aviaries, not attending shows or races, and no sales of birds.
Within the aviaries, the affected birds should be isolated to hospital cages away from other aviaries and quarantine cages. In no circumstances should birds be moved from affected aviaries to unaffected aviaries. This includes all birds no matter how valuable they are or how well they look. In an outbreak a bird that appears healthy may be incubating the disease, be a carrier or simply transfer infectious organisms that are stuck to its feet or feathers.
Alter your own movements so that the affected aviaries and hospital cages are the last visited. If you need to move from sick birds back to healthy ones, change your boots and clothes. Wash your clothes, equipment and feed and water bowls with a disinfectant such as Trigene or F10 (see Appendix 3, Recommended disinfectants).
Allow no unessential visitors until the outbreak is over. As a birdkeeper, if you visit an aviary with sick birds make sure you shower and change your clothes and shoes before dealing with your own birds.
Post mortems/Diagnostic testing
The most important tool in dealing with a disease outbreak is to find out exactly what disease you are dealing with. Some infectious diseases can be treated successfully, others may mean that birds need to be permanently isolated, or killed to contain the disease outbreak. Getting an early diagnosis can limit the damage done to your flocks so seek help early. Getting a diagnosis may entail examination and testing of live affected birds, or post mortem examination of fatalities. Getting birds to the diagnostic laboratory in good condition improves the chances of getting the diagnosis early. In severe outbreaks of disease it may be necessary to send affected birds to the laboratory still alive. The birds are then euthanased and an immediate post mortem examination occurs resulting in the best possible results.
It is important in any disease outbreak to work closely with a veterinarian. Provide as much information as possible to both the veterinarian and the diagnostic laboratory as this will aid them in resolving your problem.
When is a disease outbreak over?
This is a vitally important question to be able to answer as it will decide when you can start showing birds, returning to a normal routine and start showing, selling and bringing new birds into the aviary. The answer unfortunately is not the same for all diseases. Again this highlights the importance of getting an accurate diagnosis.
The worst case scenario is that a disease becomes endemic within your aviaries. This means that you are no longer seeing large numbers of deaths or illness but you haven’t got rid of the disease. Infectious organisms still exist within your aviaries and result in carrier birds, occasional deaths, possibly infertility, reduced reproductive performance, chick deaths, or periodically off-colour birds. If a disease becomes established like this in your aviary you may suffer from the deaths of any new birds you introduce into your aviaries or any birds you sell may introduce the disease into a new aviary and start the disease cycle all over again.
In most cases, if a diagnostic test exists, you should do multiple tests to determine you are free of the disease and do regular follow up testing. If no diagnostic test exists you should work closely with a veterinarian to establish if you can be truly free of the disease. In some situations the only way of ensuring freedom from a disease is to destroy all the birds, thoroughly disinfect the premises and then bring in new birds. This strategy of depopulation and repopulation is a last resort and heartbreaking for most birdkeepers.
Exotic diseases to New Zealand
We are extremely lucky in New Zealand to not have many devastating diseases present in the country. Given that there has been active smuggling of birds into the country this is more due to good fortune than good management practices. The entrance of a new disease could result in devastating losses to all birdkeepers and send to extinction many of our native species. If you knowingly take in illegally imported birds you are doing a great disservice not only to your fellow birdkeepers but to all those involved in trying to conserve our wildlife.
The Ministry of Agriculture and Forestry will investigate all outbreaks suspected to be a new disease in New Zealand. In most cases the birds in contact will be seized and likely destroyed. Nobody wants this to happen to a fellow birdkeeper but in many cases it is the only way to ensure a new disease does not spread off the property. Veterinarians and pathologists are required by law to report any suspicion of an exotic disease.
The best way to ensure you are not put into this situation is to:
1. Never deal with someone you know is illegally importing birds.
2. Always try to find out the history of the birds you are buying.
3. Be very wary of a cheap deal on a rare species in New Zealand.
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