Reducing ventilation at the beginning of incubation avoids unnecessary cold air from outside entering the incubation chamber. Since the moisture is retained in the closed incubator, there is also no formation of a cold spot by the humidifier. Therefore, closing the valves during the early days of incubation improves temperature uniformity and heat transfer in the eggs, creating a uniform environment for embryonic development to continue—and an ideal start to achieving a short hatch window.
However, hatcheries are also aware that if ventilation is closed for several days, overall weight loss may be affected and relative humidity levels may become too high. This is especially true in climates characterized by high humidity.
For optimal chick quality, high (above 75%) relative humidity should be avoided during the first seven to ten days of incubation because this forces compensatory weight loss to occur during last days incubation through low settings (40% or less) relative humidity. The latter can affect hatchability and chick quality because the very dry atmosphere during the last few days in the setter increases evaporation from the allantois cavity and embryonic tissues such as skin and legs.
It is generally accepted that for optimal hatchability and chick quality, eggs should lose 11-13% of their initial weight during the first 18 days of incubation. The weight loss of a hatching egg is the result of the continuous evaporation of water from the egg - and is inseparable from the ventilation function, which helps remove moisture from the incubator.
Because eggshell is porous, evaporation of water from the egg begins immediately after the egg is laid and continues throughout the course of sorting, storing and incubating eggs. Evaporation of water from eggs—and therefore weight loss—is primarily a physical process, driven by differences between internal and external vapor pressure. Internal vapor pressure is primarily represented by the saturated vapor pressure in the egg's air chamber, which increases as the temperature rises - thereby facilitating increased evaporation (weight loss) at a certain relative humidity. In high humidity conditions, weight loss is limited. For example, if the relative humidity in the incubator reaches 75%, the daily weight loss of eggs is only half that observed at 50% relative humidity.
It can be concluded that closing the vent during the first three to four days of incubation is beneficial as it maintains uniform embryonic development of each egg in the incubator and ensures a short hatch window. Subsequently, ventilation should be gradually opened to maintain optimal daily weight loss.
For incubators with programmed valve position:
Start ventilation after 3-4 days of incubation at a low level to avoid keeping the relative humidity above the set point for too long.
Keep relative humidity at 50-55% for optimal weight loss. You can also practice gradually reducing humidity from 60% to 45%, but no more.
Do not over-ventilate: open valves always disturb the internal climate of the incubator, which affects humidity, CO2 and temperature.
For incubators with automatically controlled valve position:
Set the relative humidity to 50-55% (or gradually decrease from 60% to 45%, but no less) and the maximum CO2 level to 0.4%.
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In our difficult times, when prices for goods are rising at an inexorable pace, you will always find an area in which you can profitably apply your practical skills and theoretical knowledge. Looking at the cost of an incubator manufactured in industrial conditions, you can easily calculate the benefits of self-made similar device. Moreover, making a home incubator with your own hands is not so difficult.
This is what a forum user says about his homemade incubator with mechanical egg turning geniuscat.
geniuscat
In short: incubator for 60-70 chicken eggs, the revolution is mechanical using a special grille, I don’t do it automatically at all. Heating using light bulbs, two chains. Temperature control using an electric contact thermometer. I don't trust electronics. Temperature spread across the corners is 0.5 degrees. Cheap and cheerful. If you have the components, you can make an incubator in 3-4 hours.
The most important thing in manufacturing is to ensure the ability to maintain optimal humidity and temperature inside the device, as well as create conditions for timely turning of the eggs in order to heat them evenly.
Incubator body
In most cases, the basis of everything is the body. And the incubator in this case is no exception.
During the manufacture of the case special attention Care should be taken to ensure good thermal insulation for the future device. This will allow you to avoid future troubles associated with maintaining strict temperature conditions in the incubation chamber.
For the manufacture of the case, porous polymer materials, penoplex (expanded polystyrene) 20 mm thick, etc. are quite suitable. You can also use fiberboard or chipboard sheets, but you should create double walls with foam, felt or foam core.
The size of the incubator will directly depend on the number of eggs that are planned to be placed in the chamber at the same time. The height of the internal chamber of 50 cm will be quite enough. The area of the inner base will be equal to the area of the egg tray. But you need to add about 50 mm to it on each side. This is the gap that should be between the tray and the incubator body to ensure air circulation. In the lower base of the incubator, it is imperative to drill several holes with a diameter of 10 mm, through which air exchange will take place between the internal space of the chamber and external environment(the incubator must be constantly enriched with oxygen). For an incubator designed for 50 eggs, 6 holes are enough.
Attention! The lower holes should be positioned in such a way that they are not blocked by a baking sheet (plate) with water, which will be installed in the chamber to maintain a sufficient level of humidity.
To ensure unhindered air movement between the bottom of the device and the surface on which it will be installed, there must be a gap of 30...50 mm. In its top cover there should be a viewing window 100x100 mm, covered with glass. If there is no forced ventilation in the incubator, then the glass should be opened slightly during operation, leaving a gap of 10...15 mm.
And one more nuance: one of the side surfaces of the incubator must have a door for changing water and other actions related to servicing the chamber.
Incubator tray
In order for the eggs to be carefully placed in the interior of the incubator, we need to make a special tray. In our case, it can be made on the basis of a wooden frame, which is covered with a fine mesh underneath. Both an ordinary mosquito net, used in the design of modern double-glazed window windows, and a metal (maybe different) mesh with a cell size comparable to 5x5 mm (but no more) are suitable as a mesh. In order to prevent the mesh from sagging, a couple of small slats can be nailed to the bottom of the tray, which will comprehensively strengthen the structure of the tray.
To make it more convenient to turn the eggs during incubation, the tray should be equipped with an insertable wooden grid. For convenience, you can make several gratings at once, with different sizes of internal cells. Yes, for quail eggs a grid with a cell size of 45x35 mm is suitable; for a chicken egg you need cells measuring 67x75 mm. If you want to put goose eggs in the incubator, then the cells must be of the appropriate size - 90x60 mm. The width of the grid should be 5 mm smaller than the tray itself. The length should be shorter by 50...60 mm - for quail eggs, 80...90 mm - for chicken eggs and 100...110 mm - for goose eggs. Thus, by moving the grill along the tray, you can turn the eggs 180 degrees. In order to heat the eggs evenly over time, a similar procedure should be performed approximately once every 2 to 3 hours.
Egg turning tray
The height of the sides of the tray itself should be 70–80 mm. The tray should be installed on legs 100 mm high.
This is the simplest tray design, allowing you to turn all the eggs at the same time. But in order to make the incubator design more modern, the process of turning eggs can be automated. And this will require some technical improvements.
How to make a revolution in an incubator
In order to automate the process of turning eggs in the incubator, it is necessary to introduce an electromechanical drive into its design, which is activated after a certain period of time (as we have already said, it is 2–3 hours). The accuracy of the time interval will be ensured by a special time relay. The relay can be purchased ready-made. Those who like to tinker with microcircuits can make it themselves, using electronic or even mechanical watches, which are easy to buy in Moscow and in any village, as a basis.
Here's what user FORUMHOUSE writes about this.
mednagolov
Nowadays it is easy to purchase Chinese electromechanical relays with a 24-hour cycle. In essence, this is a basic watch with a plug that plugs into a socket, and on the body of this watch there is a socket into which the consumer plugs, inside the clock a tiny electric motor turns. There is no need to wind them up; along the circle of the dial, marked out for 24 hours, there are “pressers” with which you set the time intervals.
The electric motor must transmit torque through the gearbox. This will help make the grate move smoothly and keep the eggs intact.
The tray grid should move along the guides. The walls of the tray can play the role of guides. But to avoid accidental jamming, this mechanism can be improved. To do this, a metal axis protruding from both ends should be attached along the central axis of the grille. She will play the role of a reliable guide. The axis will be inserted into special grooves made on the sides of the tray. This design is reliable, it can be easily assembled and, if necessary, quickly disassembled.
In order to drive the grid with eggs, we need a reciprocating mechanism consisting of an electric motor, a gearbox, a crank mechanism and a rod connecting the drive to the tray grid.
A device for turning eggs in an incubator.
As an electric motor, you can use special “motors” for microwave ovens, which are commercially available. Also, some craftsmen create an electromechanical drive based on the mechanism that is part of car wipers. Or here’s a way out of the situation that forum member Mednagolov came up with: the drive of the egg turning mechanism is electric. engine ball valve remote control d=3/4 220v (has an extremely powerful and durable gearbox, as well as microswitches for end positions).
He used the power supply from an old computer, and the time relay - a mechanism from a Chinese watch, which was written about just above.
The mechanism functions as follows: the relay closes electrical circuit after a specified period of time. The mechanism is driven and moves the tray grid, turning the eggs. Then the limit position switches (limit switches) are activated and the grille is fixed in the opposite extreme position. After a specified time, the cycle is repeated, and the grate returns to its original position. The entire homemade process occurs without human intervention.
Incubator heating
Proper placement of heating elements in the incubator chamber is the key to success, ensuring the hatching of healthy and strong chicks. It is customary to use ordinary incandescent light bulbs as heating elements. Ideally, they are best installed above the tray with eggs, evenly spaced around the perimeter of the incubator. The tray and the heating element must be separated by a distance of at least 25 cm. In a homemade incubator, low-power light bulbs of 25 watts, etc. should be used. The total power of the heating elements used in such an incubator should be 80 watts - for a device designed for the simultaneous hatching of 50 chicks.
The lower the power of the heating elements, the more uniform the heat distribution in the incubation chamber.
When placing lamps on the walls of the chamber, you should also ensure that they are evenly positioned around the entire perimeter. Know that by using a series electrical connection of heating elements, you can significantly extend their service life. But the power of each consumer in this case will be halved. This should be taken into account when calculating the number of heating elements, because with the appropriate connection method the number of consumers will have to double.
Temperature control
As we already know, the temperature in the incubator chamber must exactly correspond to the specified parameters. Otherwise, such a device is worthless. Optimal for hatching chicks in artificial conditions is a temperature from 37.5 to 38.3º C. But it should be strictly observed. A regular thermostat, which can be purchased in a store without any problems, will help maintain the set range. It is necessary that this device provides an accuracy of temperature values corresponding to 0.2º C. An error greater than the presented value can be detrimental to developing embryos.
We think it will not be difficult to connect a thermostat to the heating elements for a person who has decided to make an incubator with his own hands. The main thing is to ensure that the temperature sensors are located near the egg tray. For more accurate readings, the sensors can even be mounted on a tray. As an additional means of control, a regular thermometer should be used. It is better if it is electronic, capable of displaying tenths of a degree. But in extreme cases, a regular alcohol thermometer will do. It should be secured in the chamber in such a way that it is located immediately above the tray. In this case, its readings can be taken by looking through the viewing glass.
Heat accumulator
JG_ FORUMHOUSE member
To make the temperature drop more slowly, you need to use a heat accumulator. I used water as TA. It provides humidification and also increases the temperature, and when turned off, it releases it for a long time, not allowing the temperature to drop quickly. Only the container with water should be large. You can just put a metal pancake or a dumbbell inside - why not?
It remains to add that without an air humidifier in the incubator, all your efforts are doomed to failure. Therefore, a baking tray or open plate filled with water can be considered one of the essential elements involved in the incubation process. As for the heat accumulator, a heating pad or plastic bottle with water will never be superfluous in the internal space of your incubator.
Humidity can be monitored using a psychrometer, which can be purchased at a hardware store. The optimal humidity in the incubator should be 50–55% (immediately before hatching the chicks, it can be increased to 65–70%).
Incubator ventilation
Many owners of homemade incubators believe that the fan is an integral part of such a device. But practice shows that a small incubator, the number of eggs in which does not exceed 50, can do without forced ventilation. Air convection in it occurs naturally and this is enough to support the vital activity of the embryos.
If the chamber of your incubator is designed for a larger number of eggs, or if you want to create an ideal microclimate inside the device at all costs, then for these purposes you can use special fans with a diameter of 80 to 200 mm (depending on the volume of the chamber).
The fan can be mounted in the top cover of the incubator so that it takes air from the interior of the chamber. Part of the air flow will go out, and the main volume will be reflected from the lid and pass over the lower supply openings, mixing warm air with cold and enriching it with oxygen.
That's probably all. You can find out the various opinions of our users regarding the design, as well as get acquainted with their practical developments in this topic. We also have information for those interested in productivity. If you want to create more at home, the design of which contains powerful components and complex ventilation circuits, then you should visit this section.
As can be seen from the table, the release of carbon dioxide slowly increases until the allantois closes, and then increases sharply.Remembering that in normal atmospheric air contains approximately 20% oxygen, the respiratory coefficient is 0.73, and one cubic meter of air weighs 1.24 kg under normal conditions, we find that when incubating eggs it is necessary to supply for every 1000 eggs. incubated chicken eggs from 0.01 to 1.0 m3 of air per hour.
Calculation:
The required mass of oxygen MO2 per 1000 eggs is equal to the mass of carbon dioxide released.
Required air mass Mw per 1000 eggs Mw = MO2* 5 M min = 0.5*5 = 2.5 g/hour
M max = 65.3*5 = 326.5 g/hour
The required volume of air Vв per 1000 eggs is equal to Vв min = 1240/2.5 = 0.002 M3/hour
Vв max = 1240/326.6 = 0.26 M3/hour
Taking into account the respiratory coefficient Vв min = 0.002/0.73 = 0.003 M3/hour
Vв max = 0.26/0.73 = 0.36 M3/hour
Taking into account the losses of the supplied air volume due to leaks and other losses, it is advisable to increase these calculated data at least three times. As a result, we get fluctuations in air consumption per 1000 units. eggs ranging from 0.01 M3/hour to 1 M3/hour.
When supplying dust-free air for simultaneous incubation of 100,000 pcs. eggs, the hatchery room can receive from 100 to 200 mg of dust every hour or from 2 to 4 grams of dust daily.
At first glance, such a tiny amount of dust in the air seems insignificant, but it is more than enough to infect day-old chicks with pathogens of infectious diseases, especially in difficult epidemiological conditions at the enterprise.
There are several ways to remove dust from the air entering the hatchery, one of which is to filter all air supplied to the room through an industrial filter, which filters the required volume of air not only from dust, but also from the microorganisms it contains. This method is quite effective and is often used in a number of microbiological industry enterprises. However, along with obvious advantages, this filtration method also has disadvantages, including the relatively high cost of installed equipment and filter elements (for example, Petryanov fabric). After filtering the air through such a filter, it must again be brought to the required temperature and humidity conditions. That is, the air purification and air conditioning system turns into a multi-stage system that can occupy a significant amount of production space.
We tried to solve all of the above problems using a simple device, the diagram of which is shown in Fig. 6.
Air coming from outside, passing through the closed chamber of the device, is irrigated with water through the built-in nozzles, then the excess water condenses and purified air leaves the device. The device is designed to heat water to a predetermined temperature. The water level in the device’s bathroom is controlled by a level sensor (LS). As water is consumed, replenishment is turned on to the required level.
An incubator is a fairly simple design, which is characterized by certain nuances. In particular, necessary condition for high-quality incubation - the presence of a certain temperature. Most people think so, but in reality many other factors, such as humidity levels, also matter. To provide correct mode operation of the incubator, it is necessary to properly organize ventilation.
Therefore, we will figure out how to make ventilation in an incubator with our own hands, and what is needed for this.
About the importance of air exchange
There is one simple axiom: proper ventilation guarantees a higher chick yield. Let's not forget that oxygen supply is required, and this is extremely important for embryos. Also, with a properly organized system, carbon dioxide (it is formed as a result of the respiration of chickens in the egg) is released into the environment through special holes.
Calculation of ventilation for an incubator must take into account how the embryo develops:
- sixth day – slight absorption of oxygen begins;
- sixteenth day - each egg requires about two and a half liters of air in 24 hours;
- the day before hatching - each egg needs eight liters of air.
Poor ventilation in the incubator causes the death of embryos.
Device Features
There are two types of ventilation:
- Constant. Regular air movement is created in the chamber, so air changes are carried out constantly, as is uniform heat distribution.
- Periodic. Ventilation operates once every 24 hours, changing the air in the chamber.
And here you need to remember that even high-quality, uniform ventilation is not a reason to refuse to turn eggs. This is the only way to avoid the embryo sticking to the shell.
Constant
It happens like this:
- A fan from the chamber forces air masses, which causes the flow to enter the holes, and then discharge it out. The main flow comes from the roof.
- The flows catch fresh air, there is a mixing of old and new masses, the flow passes through the heaters.
- Then the stream goes down, where it is moistened by the water in the tray.
- After this, the air masses give off heat to the eggs.
- Then they return to the fan again.
This principle allows us to accomplish three tasks:
- hydration;
- ventilation;
- heating.
Periodic
Series production models ventilate automatically. This happens once a day. If the device is made by hand, then most likely it is controlled manually. To ensure automatic processes, a controller must be present in the design.
Ventilation occurs as follows:
- the chamber is heated;
- the fan starts working, providing air change in the device, the eggs are cooled;
- after 15-30 minutes the heating turns on again and the fan turns off.
This approach improves embryo development.
Equipment
When thinking about building a ventilation system with your own hands, you need to take into account the factors affecting air exchange:
- power supply 220 Volt;
- fan diameter can be 8-40 cm;
- productivity – 40-200 m 3 /hour.
It should be remembered that a filter must be installed in front of the fan, which will prevent the accumulation of fluff.
To ensure ventilation of a powerful incubator, you need a more serious solution - a supply and exhaust system. The use of such a device reduces costs and improves air exchange.
Foam device
Let's look at how ventilation works in a foam incubator. The design shown in the photo should provide a gap between the tray and the wall - up to 8 cm. If the incubator is large, holes must be made in the foam to release carbon dioxide.
The fan must be installed so that it does not blow on the eggs, otherwise they will dry out. Therefore, it should be directed upward, where the holes are located - up to 3 pieces with a diameter of 1-2 cm. Since part of the air masses will be removed outside the chamber, air exchange will be improved, which increases incubation rates.
The fan can be taken from the power supply of a desktop computer with a voltage of 12 V. You can use charger from a mobile phone, rated for 5 V. The fan will also work from it. An excellent solution is an regulated power supply that produces a voltage of 3-12 V. This will allow you to first supply power up to 5 V, and then, before outputting, add voltage, improving air exchange in the foam incubator.
Refrigerator device
Ventilation holes can be made both at the top and bottom. Tubes are inserted into them, since the glass wool located under the casing will impede the movement of air masses. Manual adjustment This is done by temporarily blocking some of the holes, for which you can use cotton wool. A fan can be installed at the bottom of the incubator from the refrigerator.
In this way, fairly uniform ventilation should be achieved in a homemade incubator from the refrigerator.
Let's sum it up
Whatever the incubator, whether you make it yourself from a foam box or from a refrigerator, ventilation can be done taking into account the necessary conditions. The recommendations given should help organize everything with high efficiency.
In addition, you can also watch how to make ventilation in an incubator in the video.
There are two different small incubators, one with a fan and one without. They are called, respectively, “with artificial ventilation” and “with natural ventilation”.
Often, users find it difficult to choose between them. The difference in how eggs are heated is very important, but not always adequately appreciated. Here we present a few thoughts.
To achieve a good constant temperature around the perimeter, naturally ventilated incubators (those without fans) draw heat from the level above the eggs and exhibit a significant temperature difference between their top and bottom levels. That's why upper part eggs are generally 4°C (7°F) warmer than the bottom.
Installing a fan in the incubator dramatically changes the situation and eliminates the temperature gradient at all practical levels. Placing eggs at different levels in the same device dictates the necessary condition of mechanical air circulation so that all eggs are provided with the same temperature.
However, since many of us are concerned with the relatively small number of eggs that can be placed on one level, there is a real choice.
At the same time as eliminating temperature gradients, the fan also eliminates differences in Relative Humidity. RH is very closely related to temperature (see Brinsea® fact sheet “Humidity in Incubation”) so (for a given level of moisture in the air) relative humidity decreases sharply as temperature increases.
The diagram shows the types of temperature and humidity variations that can be expected inside a naturally ventilated incubator.
Accurate measurements of RH and temperature can be quite challenging in naturally ventilated environments. In practice, it is quite difficult to measure (or control) temperature or humidity when the average temperature varies across the height of the egg.
Sensors placed between eggs are susceptible to damage and contamination, thereby causing inaccurate measurements due to direct contact with eggs or chicks. One thing to remember is that the metabolic heat of the embryo will increase the temperature of the egg beyond what you are trying to control. Thus, control and measurements in naturally ventilated incubators are carried out over the eggs, which requires slight adjustments to account for the temperature gradient.
The temperature gradient also varies on its own, depending on the external temperature. In cold conditions, it is necessary to increase the temperature on top of the eggs slightly to achieve an equal average temperature as the bottoms of the eggs are now cooler. Even a thermometer can be affected by temperature gradients. A slight increase in reading will occur because the thermometer stem is in a slightly warmer zone than its reservoir. This happens when convective heat exchange between the rod and environment slightly increases the temperature of the tank compared to the surrounding air.
All these complications can be completely avoided by simply installing a fan. Almost all experiments conducted by researchers studying incubation processes are carried out in artificially ventilated conditions. This eliminates a number of errors and creates predictable conditions.
So why bother with natural ventilation? Here we enter an area filled with subjective opinions and prejudices. Of course, the fan adds to the cost of the device. That is, cheaper incubators are usually equipped with natural ventilation.
Naturally ventilated incubators must be better insulated than those equipped with fans to keep the temperature gradient within reasonable limits.
Insulated enclosures are usually more expensive unless they are made of foam.
An even more important factor than price is the little-researched question of how eggs grow under temperature gradients versus artificial ventilation. Experiment with mock-up eggs filled with sensors and placed in nests wild birds, shows that a significant temperature gradient is a normal condition in natural conditions.
In addition to the above, quite wide deviations occur that can be regarded as highly suspicious in the incubator. Brinsea's experience over many years of making incubators shows that there are a significantly larger number of users of naturally ventilated incubators who achieve satisfactory results. Brinsea achieved virtually identical results with both types of devices in their own laboratory with a range of eggs from different species.
In their opinion, eggs incubated under conditions with a temperature gradient similar to natural conditions, are more tolerant of “less than ideal” settings. It is also possible that wild bird eggs are more adapted to the more “natural” conditions of naturally ventilated incubators. After all, they have not been subject to artificial selection for countless generations to prefer artificially ventilated conditions.
Enough with theories. Let's move on to more practical observations.
Temperature
Most birds are incubated at an average temperature of 37 to 38°C (98.6 to 100.4°F).
Waterfowl are most comfortable at temperatures between 37 and 37.5°C (98.6 and 99.5°F). In artificially ventilated incubators, this temperature will be displayed on the thermometer.
In naturally ventilated units, the temperature displayed will depend on the location of the thermometer, which is quite critical - follow the placement instructions carefully. Also, the temperature will depend on the design and temperature gradient of the incubator; again, follow the instructions.
In the absence of instructions, place a thermometer in close proximity to the tops of the eggs and run the incubator with the temperature set at 39 to 39.5°C (102.2 to 103°F). It is important to understand that no incubator will create an ideal temperature distribution. Heat loss from the enclosure must be balanced with the heat generated by the heater. The process of transferring heat from one host to another is usually accompanied by a drop in temperature - even with a fan - and this drop will mean that some eggs are warmer than others. To keep this difference minimal, keep the incubator in warm, stable conditions. Ideally, install an electric convection heater equipped with a thermostat to keep the room temperature at 20-25 degrees day and night.
Removal
Low air speed and high humidity provide better results. In mechanically ventilated incubators, RH levels should be high (70% or higher) to prevent excessive drying of exposed membranes. In naturally ventilated incubators this problem is much less serious, and a sharp increase in humidity accompanies the birth of birds and helps those about to hatch. The hatcher temperature is typically kept 0.5°C (1°F) lower than the incubation temperature to compensate for the high metabolic activity of the hatching chicks.
Bottom line
Improvements in incubator design, coupled with lower costs for reliable electronic temperature devices, make it possible to control incubation more closely than before. However, for non-domesticated species, a lot of work is required in selecting ideal conditions.
For example, why do eggs incubated under natural parents for the first few days and then transferred to an incubator hatch so much better than those that were initially placed in it?
Why do we find that eggs placed in naturally ventilated incubators tend to be more tolerant of variations in temperature and humidity than those placed in artificially ventilated incubators? It may be premature to dismiss natural ventilation in incubators as obsolete until incubator design can more closely replicate nest conditions.