What method is best to determine gender: DNA or surgical sexing?
The answer to this question is based more on personal choice and belief than science.
DNA sexing is simple, quick and non-invasive. You can sex the birds from the eggshell, where blood and tissue can be used to determine gender. Feathers or blood is submitted from feathering, immature and fully mature birds for similar analysis. The result is not infallible. More than one breeder will recall having DNA sexed males than laid eggs or vice versa. The collection of the genetic material, its freshness and other factors can affect the outcome. To avoid contamination of the genetic material, it is best to collect the sample using latex gloves and then placing the sample in a paper (not plastic) bag, especially when collecting blood, which can deteriorate in quality when not properly dried before being placed in a sealed plastic bag. With each subsequent sample, a new glove should be used. The intention is to prevent DNA material from one bird contaminating the sample of another bird.
I always prefer genetic sexing when it comes to small birds and also youngsters. My opinion is that small birds can be affected by the intrusion of the body with an instrument. Some veterinarians will disagree but I know of many cases where small birds like Pyrrhura conures have not bred after being surgically sexed. Their siblings were DNA sexed and have bred with no problem.
Surgical sexing is best when determining gender or adult birds whose history is unknown. During the procedure, the veterinarian can determine the reproductive potential of the bird involved. Its general state of health can also be assessed. Cloudy air sacs, deformed sexual organs, spent or scarred ovaries and more can be detected by an experienced clinician.
Surgical sexing is not infallible in the hands of an inexperienced person, who may not necessary know where to look or what the organs of an immature bird looks like.
With both methods, the rate of failure is significantly small. I can recall the days before sexing techniques were available—the advent of surgical sexing dates to about 1975, when Dr Raymond Kray and others began experimenting with a process that directly visualizes the gonads—when everyone relied on visual, behavior or the “witching” process to determine the sex of their birds. I learned that many of the birds that I perceived were pairs were in actuality two males or
two females and that witching—the process of placing a pendulum above the head, with the pendulum allegedly swinging back and forth or in a circular fashion to differentiate the sexes—was terribly flawed. I still get messages from people that swear witching works. On a few occasions I have had the possibility to prove to these people that the process is ineffective. With dimorphic species like Eclectus Eclectus roratus, the witching suggested on a few occasions that the easily distinguished males were females! This showed that witching was totally erring.
When one takes into account the ready availability of DNA sexing, it is not worth guessing what sex a particular bird is. Just in economic terms, time spend in feeding birds of the same gender will eventually have made the money spent on sexing a worthwhile investment.
3) What is the best hygiene practice that I can use in my aviary?
Many that have read my writings, visited my home or heard my lectures will know that I am a great proponent of strict hygiene in the aviary and nursery. The time and effort spent in cleaning will quickly repay itself in fewer health issues. How do I define hygiene?
I prefer suspended enclosures for housing parrots, though understand that some terrestrial species and climatic conditions make the traditional walk in aviaries more practical. My favor of the suspended cages is because they allow feces and spilled food to fall out of reach of the birds. In traditional walk in aviaries, the birds can descend to the floor, walk amongst their droppings (which they will clean from their feet with their tongue and beak when they return to a perch) and eat food that dropped to the floor, which could be spoiled. Because of this, the risk of parasite infestation is greatest in a traditional walk in enclosure. A cement floor with a drain that allows the floor to be washed is best for the standard aviaries. For the suspended enclosures, any substrate is suitable, including a dirt floor, because the birds cannot reach the ground.
The worst cages are those that have a dirt, gravel or wooded floor. Dirt is impossible to disinfect. Traditionally the method to clean such cages is to remove the occupants once a year, turn the ground and then lime it, returning the birds after a period of time. Gravel is better if it sits on a porous floor that will permit washing. Wood is porous and can never be cleaned thoroughly. I write this from experience. In 1978, when I was starting in aviculture, I acquired some very nice cages that had wooden floor. The idea was that I could cover the floor with shavings. Cleaning them proved nightmarish and breaking the cycle of ascarid worm infestation in Slender-billed Conures Enicognathus leptorhynchus proved so difficult that I lost several birds. I was fighting a losing battle. The cycle was broken when the birds were transferred to suspended aviaries. I stress that wooden and dirt floored aviaries be avoided because in South-East Asia and India they are still commonly used. Many of these breeders are continuously writing to ask for advice on treating sick birds. The problem is that treatment is merely forestalling another outbreak as the cycle of reinfection cannot be broken.
Cages with a grid are best. A tray that collects falling debris is optimum for maintaining hygiene.
How bowls and cages are disinfected is important. Simply washing with copious amounts of water or using a sponge soaked in a disinfectant is ineffective. Most disinfectants work best when they are not in the presence of organic matter.
This means that food and droppings should first be washed away. Soapy water is ideal for this. Afterwards, water can be used to remove the soap. Immediately afterwards a disinfectant can be used, followed again by a rinse.
In my collection, bowls are disinfected in the following manner. They are soaked in water to soften any bits of food or the occasional dropping. Each bowl is then cleaned using soapy water. The bowls are rinsed and then soaked in a chlorine bleach solution. They are allowed to soak for 5 minutes. The bowls are then rinsed again. We have the advantage of living in south Florida, where the sun is bright for the majority of the year. The bowls are placed on racks in the sun to dry and for additional disinfection by the sun´s rays. Once dried, the bowls are stored on a shelf in a room where there are no rodents or insects. The bowls are distributed from a cart—they are never allowed to touch the ground. I stress not allowing them to come in contact with the ground because from Panama to India, from Europe to the Pacific I have visited collections where the clean bowls come in contact with the ground, effectively undermining the disinfection process.
My cages and aviaries are cleaned with a hose. Originally we used a pressure cleaner but the pressure of the water can disperse fomites. We now use a hose with a fine spigot. Soapy water from a bucket is applied using a plastic brush, insuring that the feed hatches and the wire mesh are scrubbed. The soapy water is then rinsed and a chlorinated bleach solution from a spray bottle is applied. If birds are inside the cage, extreme care is taken that they DO NOT come in contact with the bleach. The cage is finally rinsed with copious amounts of water.
Hygiene is probably the most time consuming task in an aviary or bird room but it can save countless losses of valuable stock.