Each breeding season, aviculturists across the globe will be faced with issues common in nesting parrots: the birds will prove anything but reliable parents. Unless the breeder takes the initiative, the eggs or chicks will be lost.
The decision to artificially incubate a parrot egg can be made based on several scenarios: the hen does not incubate or has fallen ill, one or both members of the pair break eggs, there has been the onset of a climatic condition (such as excessive rain or cold) that can affect natural incubation, the breeder is interested in boosting production, the egg shell is aberrant (too thin or too thick), or the egg has a malpositioned air cell, cracks, fissures or has bubbles. Such eggs can be removed, repaired or treated depending on the condition—a hyper humid incubator in thin shelled eggs, injecting antibiotics in an egg with bubbles, etc– in order for the embryo to develop. At hatching a chick that is malpositioned or that is encapsulated in an overly thick-shelled egg can be assisted to hatch. These problem eggs would rarely survive in the nest.
With most parrots, including such seasonal nesters as Asiatic parakeets of the genus Psittacula and Amazon parrots (genus Amazona), the breeder can significantly boost production by taking the first clutch and then letting then hen incubate. As an example, a pair of Yellow-shouldered Amazons Amazona barbadensis will produce one 3-4 egg clutch once a year if allowed to incubate and rear the young, but if the eggs from the first clutch are removed as they are laid, the hen in all probability will lay a larger clutch than normal, perhaps containing 5 and less commonly 6 eggs. After a span that is normally the same as the incubation period (26-28 days), almost all hens will lay again, typically a clutch of 3-4 eggs, which she can then incubate, hatch and rear to fledging. With some effort, the breeder can rear twice the number of chicks from the same pair. This is very important when dealing with a rare or endangered species.
The process of artificially incubating parrot eggs is not as easy as may believe. You simply do not put the eggs in the incubator and wait for the chicks to emerge. You must monitor the eggs daily, must vary the humidity to control weight loss in the eggs and must turn the eggs daily to insure that the embryo develops properly. All of these factors can vary with the species and even with the breeder. As an example, the late Howard Voren believed that turning should cease the minute the egg is enveloped in veins; the veins look like a spider web and grow underneath the shell, allowing the exchange of air and the absorption of heat; the hen sits on the egg and incubates only one side, which is where the embryo will position itself; this is why the yolk moves invariably to the top inside the egg. The bottom of the egg, the side sitting on the nest bottom, is always cooler. Some incubators copy this system to insure that incubation is as natural as possible. How many times the egg is turned each day varies with breeders. Most incubators turn the eggs 12-16 times daily, typically turning it backwards and forward just slightly. I always turn the egg manually once a day to insure that the embryo never returns to the same exact spot the next day. The incubation temperature should be 37.3-37.4ºC. Humidity affects the development of the embryo indirectly; in most eggs a weight loss of 14-16% from the time the egg was laid is normal until the point the chick starts to hatch. This weight loss allows the chick to hatch dry and facilitates breathing and development. Most eggs that fail to hatch perish because the incubation temperature was inadequate (as evinced by an unabsorbed egg yolk at hatching or during necropsy of the dead egg) or from too high a humidity, which causes the embryo to drown in its own fluids. Mechanical failure contributes to the first means of mortality, but avicultural perception and intervention contribute to the latter. This is because most people believe that the incubation humidity should be at saturation. Nothing is further from the truth. I incubate all my parrot eggs in a dry incubator. The chicks hatch normally and never display signs of dehydration. The incubator utilizes the ambient humidity, which oscillates around 48%. At such humidity I have hatched species ranging from macaws to cockatoos, from African to Asiatic parrots and everything in between. The eggs have ranged from those produced by Green-winged Macaws Ara chloropterus, which are as large as those of a chicken egg to the tiny eggs produced by Brotogeris parakeets. The incubator temperature and humidity have been as indicated above.
So now that we have an understanding of incubation, what are important requisites when selecting an incubator:
- The unit should be able to maintain the heat. Slight fluctuations are normal. They occur when a hen emerges to feed or defecate. However, long term chilling or a unit that is unable to keep the eggs at the required temperature (37.3-37.4°C) will result in dead embryos. I like doors that open from the front. Because heat rises, a door at the top will mean complete chilling each time an egg is inserted or removed or examined.
- The incubator should be able to turn the eggs at least 12 times daily. To rely on manual turning is fraught with problems. The turning should be slight and smooth; jarring can cause a series of problems that will affect the embryo.
- The unit should be easy to clean and disinfect. All incubators need to be disinfected or fumigated at least once each breeding season.
- Depending on ambient humidity, the unit should have a water receptacle. This unit should only hold distilled water to prevent mineral deposits from building and affecting the wick that gives the hygrometer (humidity) reading.
- The unit must have a fan that circulates the heat. The fan should not be so strong that one creates a tunnel effect. Still air incubators (meaning that there is no system to circulate the air) are not in my opinion suitable for hatching parrot eggs.
- The unit should come with a thermometer. I always recommend acquiring a second digital thermometer to verify that the unit is indeed capable of maintaining the required heat. We check the heat in the corners of the incubator, which tend to be cool spots, also near the door. This allows us to ascertain that the unit operating efficiently.
I always recommend keeping the unit operational during the entire breeding season in case an emergency arises. Hatching parrot eggs requires some effort and the following of some methodical steps. If these steps are taken, the hatch rate can be as high as it would be under the biological parents.