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Husbandry

THE FOLLOWING INFORMATION IS BASED ON A PRESENTATION BY DR. MICHAEL TAYLOR, AVIAN EXOTIC MEDICINE, OF GUELPH UNIVERSITY, GUELPH, ONTARIO, AT THE 11TH ANNUAL PARROT SYMPOSIUM, 2000, IN TORONTO, ONTARIO, CANADA, AND IN CONVERSATION.
 

Despite the fact that testing for PDD remains in the experimental stages, and no one definitive test or treatment currently exists, there are steps you can take to avoid the spread of this disease throughout your aviary.   To this date, there is no proof to suggest that this virus is airborne and in fact, all evidence points to transmission of this virus through body fluids.   Given these known characteristics, Dr. Michael Taylor, head of avian and exotic medicine at the University of Guelph suggests that, once PDD is discovered, the most effective tool currently available in preventing the spread of this disease is strict attention to husbandry.

Consider for one moment that in aviaries where husbandry is impeccable, it is not unusual to find a PDD positive bird surrounded by uninfected neighbouring birds.   These findings  underscore the importance of husbandry as a critical component in curtailing the spread of PDD throughout an aviary, particularly as it relates to transmission by fecal matter.

Many of us consider our husbandry to be beyond reproach; we clean daily, pay attention to disinfection of cups etc.,  and maintain what is ostensibly, a hygienic aviary or pet care program that we are proud of.    However, following an outbreak of PDD in your aviary or in your pet home, an honest appraisal of your husbandry can often reveal the means of transmission.

Let me stress that the “honesty” with which you approach this appraisal can be the determining factor in limiting the spread of PDD once it is suspected in your flock.   The following factors were outlined by Dr. Taylor as factors deserving careful consideration in aviary management following an outbreak of PDD.

Birds at liberty:

Unrestricted movement of birds in an aviary is a particularly effective vehicle for the spread of PDD.   In fact, following the discovery of PDD in aviaries, epidemiological studies have often traced transmission throughout the aviary back to escapees and other birds that have been allowed to fly free.   Birds a liberty are free to land on and defecate into other cages which is an incredibly efficient method of transmitting PDD between individuals.

If you are allowing this to occur in your aviary, regardless of how inadvertent, steps to curtail the free movement of your birds between cages is essential.   For some aviculturists this will mean the installation of more secure locks on the cages of our more adept escape artists.   If, like many a parrot owner, allowing your bird to fly free in your aviary is an important and enjoyable component of your program or pet home, you may want to consider removing individual birds to another room, or you may chose to maintain an enclosed flight area that can be disinfected between uses.

Cross contamination:

Feed and water cups can provide another efficient mode of viral transmission.   Given the importance of limiting fecal cross contamination, Dr. Taylor suggests the implementation of a two bowl system.    This feeding system is comprised of two separate stages using two complete sets of stainless steel bowls for each cage.   The dirty sets are removed from each and every cage in one process and placed away in an area to be cleaned.  The second stage follows with the replacement of clean feed and water bowls in each cage, being careful not to transmit fecal matter while performing this task.
 

Cages:

Maintaining a  large number of birds in close proximity increases the likelihood that an organism can be transmitted from one individual to another.   As aviculturists, we are all familiar with the spray area found around the base of our cages.  This is the area within which fecal and all other matter from the inhabitants of each cage settles after if falls or filters to the floor and is typically a few feet in width around the perimeter of each cage.

It is important that neighbouring cages are placed outside the “spray” area of their neighbours.   The spread of fecal and other matter leaves birds in close proximity to their neighbours especially susceptible to infection by coming into contact with this “spray” material.
 

For side by side cage set-ups, barriers placed between cages can help somewhat by preventing the spray from contaminating neighbouring cages.  To achieve this, the use of tarpaulins or other solid barriers constructed of Plexiglas or the opaque plastic building materials found at local hardware stores can be a relatively low cost means of constructing a barrier.   The most effective means of eliminating this problem is to avoid overcrowding.

In light of this information, breeders particularly, may want to reconsider the concept of stacked cages.   Simply by virtue of their design, stacked cages leave those birds housed lower on the stack in the direct line of matter while it sifts its way downward throughout the unit.  If space is at a premium, aviculturists may need to settle instead, for fewer birds in the same area.

Note:  This is a point that bears a second look.  If usable floor space in your aviary is too limited to allow for a spacious set-up, you may seriously need to re-evaluate your aviary plan and consider maintaining fewer birds in the same area.