Every species has its own incubation period, from the moment an egg was placed in the incubator up until the moment of hatching. As mentioned in a previous post, at the end of this period the egg must have already lost around 15% of its weight. Most of this weight loss occurs naturally as a result of liquid evaporating through the porous eggshell. However, if not enough weight has had been lost, then the embryo itself takes measures to rectify the situation during the last days of incubation.

As the days near hatching, the embryo self-regulates its weight loss. It does this by taking into account its cumulative weight loss and the environmental RH and peforms the external PIP at the appropriate time. The additional puncture in the eggshell increases the egg’s capacity of evaporation, enabling it to lose more weight. This means that if an embryo “feels” it’s too wet, it will make the first PIP sooner to reach an optimal condition for hatching.

When the embryo performs the external PIP, it starts breathing with its own lungs. At this moment we can hear it twitting. The twitting is the embryo’s announcement to the world: “I am alive and feeling fine…”.

Have patience though, as it could take up to three days from the moment of the first PIP until the the chick has completely hatched. Don’t be tempted to intervene and “help” the chick to hatch after the external PIP. The natural hatching process is crucial for vivid and energetic,healthy chicks. Any intervention of the natural process of hatching is dangerous and might cause the embryo to die! The Inca Incubator was designed with the crucial factors of the natural incubating process in mind, so we must avoid the temptation to interfere and let nature run its course…

Lets take a look at a real life example from our aviaries:

A clutch of Adelaide Rosella (Platycercus adelaidae) eggs was placed in the Inca Incubator 20 days ago. 19 days later we could notice the first PIP and then no change for the following 24 hours. When we checked the incubator yesterday morning at 8 o’clock, we still didn’t notice any movement but after one hour – the chick was out of the eggshell…

One more point to emphasize:  during the actual hatching, the relative humidity (RH) percentages increase  “automatically“ because of the evaporation of the egg’s fluids. Do not manually alter the humidity level at this point , as this is a very critical moment during the hatching process and crucial for the chick’s development. This evaporation process has no influence on the other eggs in the incubator but it allows the chick to hatch properly. After the chick has hatched and “dried up”, the RH will naturally return to its appropriate level.

Some breeders use less effective methods of incubation such as increasing the humidity levels before the final stage of hatching or even relocating the eggs to a Hatcher -

However this is unnecessary with Inca Incubator because the entire hatching process is happening naturally as explained here. Because of the same reason, there is no need to manually stop the egg-tray. The Inca egg-tray was designed so that it moves slowly and gently turns the eggs, in the same way this happens in nature with the brooding parent. The chick can not be hurt whatsoever by this smooth movement – it will only receive a harmless nudge…

When a breeder wants to take the eggs for artificial incubation, it is better to wait until the entire clutch has been laid and harvest from the nesting box few eggs at once. This provides better chance for all of the eggs to hatch more or less in the same time. It is good practice to leave them at least 24 hours before incubating them. Fertile eggs can be stored for up to 7 days before being incubated and it is recommended to keep them at a room temperature of between 15ºC to 22ºC. During this waiting period the eggs must be turned manually several times a day.

It is possible to determine whether an egg is fertile or not starting from day 4 of incubation, however it is advised to wait 7 days to be on the safe side. Placing an Egg Candler or another light source behind the egg allows you to observe the development of an embryo’s blood vessels around the inner surface – a sign of a fertile egg.

If after 7 days of artificial incubation no blood vessels appear – the egg is infertile and it is recommended to take it out of the incubator.

D.M.P. Engineering developed an affordable Egg Candler for poultry and all other birds. This egg candler allows you to examine fertility in both white and brown eggs as well.

Originally, parrots in the wild of different regions were adjusted to different relative humidity percentages; e.g. the Amazon, the Macaw, or the African Grey from the Rain Forests were adjusted to higher RH values than the Cockatoo, the Rosella, or the Ring Neck from the dryer areas such as the Australian Outback.

However, parrots in captivity are bred outside of their natural habitat, and therefor the RH values in these new environments might not be as optimal for egg incubation. In addition, the optimal relative humidity values for the same species could be different for various climates.

During the embryo’s development, fluids in the egg are evaporated contributing the egg’s weight loss. By weighing the egg, one can determine the proper RH value for a specific parrot at a certain climate, and adjust it accordingly in the incubator.

How to calculate an egg’s weight loss

Well-known researches indicate the ideal weight loss for an egg during the incubating process (between 18-28 days) is 15% (± 3%).

For example: A Grey African’s egg weighs 16 grams at the start of a 28 day incubation period.

The ideal weight loss during the whole incubation period would be 2.4 grams (16 grams X 15%). The weight loss during one day would be 0.0856 grams (2.4 grams divided by 28 days)

According to the calculation above, this Grey African’s egg should weigh 0.34 grams less after 4 days, meaning 15.65 grams (4 days X 0.0856 grams = 0.34 grams; 16 grams – 0.34 grams = 15.65 grams).

If the egg weight is as mentioned above, the relative humidity values inside the incubator are correct.  If the egg weight is higher than 15.65 grams, the relative humidity percentages are too high and must be lowered. If the egg weight is lower than 15.65 grams, the weight loss is incorrect and the relative humidity percentages should be raised.

It is important to mention that the RH values are never constant during the incubation process – this a normal phenomenon. The breeder should attempt to maintain an average level of the desired RH value throughout the incubation process.

Some breeders incubate many eggs by using several incubators simultaneously, each with its own different RH values, transferring eggs between them according to the eggs’ need. The lost of weight should be measured using an accurate scale every 3-4 days. This procedure might seem a bit complicated at the first, however with a little experience a breeder can determine the proper RH values suitable to his different species, even without weighing the eggs.

The relative humidity values are different from incubator to incubator and depend on the incubator’s structure and air movement within. Therefor it is not possible to compare the RH values between different incubators.

If you are uncertain of the the proper RH value for your parrot during the beginning of the incubation process, try to set an average of 65% – 70% RH level for Rain Forest parrots, and  60% – 65% RH for those from dryer areas. However, the only way to determine the proper RH value is using the process described above. Setting the RH values without without calculating the eggs’ weight loss would be incorrect and irresponsible.

 How to measure the relative humidity

As I have mentioned above, the presence of relative humidity in the incubator is an essential key for the incubation process and for successful hatching. Since humidity levels are relative and vary dynamically with changes of temperature, humidity measurements are problematic and should be measured according to the standard Temperature and Relative Humidity Charts showing the relative humidity in various temperatures.

Most of the standard humidity meters are designed to be used in a room temperature. These meters are inaccurate because a change in the room temperature causes them to display a wrong reading of the humidity level. A digital hygrometers might be housed in an attractive display, but those are generally inaccurate and one cannot determine if they deviations they display are significant or not. In addition there’s no certain way to determine whether a digital hygrometer displays  incorrect humidity.  Accurate digital hygrometers are very expensive and require periodic calibration. Several types of hygrometers exist for home use, but they are unsuitable for an incubator.

It is recommended to use an accurate Temperature / Humidity Measure, that is designed especially for incubators maintained at an average of 37.3°C and measures the relative humidity in percentages. The absence of such a humidity meter in today’s market drove us to come up with our own unique solution: the D.M.P temperature\humidity meter based on the wet\dry bulb principle.

In the meantime, why don’t you check out our blog?

“In all the professional books that I’ve read, all the experts say that each species has a different incubating temperature and the more accurate the temperature is – the better the hatching results should be”

To verify this bold statement, he used small-sized data loggers and hid them inside artificial eggs. Those eggs were then placed alongside genuine ones within the nesting box. The loggers were programmed to record temperature readings from inside the egg every 10 minutes. After a period of time, in which the eggs were under the brooding mother, David removed them downloaded the data from the loggers to his computer.

“Surprisingly, the data received from the loggers was not what I expected and painted a totally different picture. The temperature inside the again wasn’t fixed. In fact – it fluctuated between 35 Degrees Celsius and 39 Degrees Celsius and even higher - 40.5 Degrees Celsius… which makes sense because the brooding mother’s temperature is between 41- 42 Degrees Celsius. All the information,  both from the nesting boxes in my aviaries and from birds in the wild showed the same results!
Furthermore, despite the differences in temperature, the hatching results were very good…
After thinking it over, the conclusions were inevitable: if this is what happens in nature, we should create the same conditions in artificial incubation!”

The next step in David’s research was to understand what caused this temperature fluctuation. He explains:

“at first, the brooding female warms the eggs’ upper part by touching it with her body and so it gets warmer than the egg’s lower part. In addition, she rolls the eggs with her beak, moving the warm eggs away and bringing the colder ones closer. All of this during an approximate cycle of an hour & a half. However, neither the temperature changes nor the length of the rolling cycle repeated itself accurately.”

The next step was checking the eggs:

“the experts say that the air pocket inside the egg enables the embryo to breath in the first minutes before the external PiP. It may be true but this is not the main reason. In my opinion, the air pocket allows expansions and contraction of the fluids inside. When the temperature goes up, expansion occurs and the air goes out from the air pocket. When the temperature goes down, a suction is created that allows oxygen to penetrate through the porous eggshell to the embryo.
We can describe this process as “breathing” and it contributes to the embryo’s proper development. A very accurate temperature will prevent the embryo from getting the desirable amount of oxygen it needs. This theory can be supported by candling the egg after 5 days. Then you see that the first blood vessels are attached to the eggshell in order to absorb oxygen for the embryo.

While checking chicken eggs’ embryos I found presence of blood vessels attached to the eggshell until the very last moment of hatching. The embryo’s body absorbed it until he could breath independently through the hole he “PiPed” in the eggshell. Obviously this “PiP” gets made in the air pocket where no blood vessels are present.

It is important to mention that while the embryo starts hatching the breeder can hear his twittering; These are not  stress signs but an indication that the embryo has started to breath by its own. Any intervention at this stage could harm the blood vessels and cause the embryo’s death”.

The temperature’s changes are implemented in the Inca Incubators to guarantee that the embryo will receive enough oxygen to develop as best as possible. Moreover, because we replicate the natural incubating process as explained above, the chicks are stronger, more vivid and lively – and that brings an entirely different perspective to artificial incubation….

David Vishnia summarizes:

“to design a complicated and heavy incubator with many components is easy, but to design a simple, neat & light appliance that will give almost 100% hatching success rates is very hard and not always one can see the huge amount of work that was put into it…

I think that the following quotation from our testimonials’ letters will illustrates my idea:

About 3 monthes ago, the incubator at the hebrew University’s faculty of Agriculture was shut temporarily. This happened at the time we urgently needed a small incubator for research on the development of blood vesseles in the chorioalantoic membrane of chicken embryos.

When looking for a temporary replacement incubator, I was advised to approach you, as a leading producer of small incubators that can easily fit on the bench in my laboratory.

Fortunately, you responded positively to my request and allowed me to use one of your incubators for over 3 months. During this period, we incubated several hundreds of eggs in your incubator, until they reach the embryonic age of 12 days, as required for our study. In the last round, we incubated to eggs all the way to day 21, when the chicks nicely hatched in your machine.

During the use of your incubator, we have been deeply impressed by its sophisticated simplicity. One may think that simplicity and sophistication reflect opposite characteristics, but based on my life-long experience, I know that it take high level of sophistication to produce a product like your incubator, which is characterized by simplicity and reliability.

We wholeheartedly thank you for letting us use your incubator, and for the opportunity to get to know you and your novel and creative contributions to incubation.

Sincerely,