Incubation

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Jacob Springs and Agronimo's prototype Henmulator arduino controlled incubator


Incubation is the process of creating an artificial environment for hatching eggs, usually of birds of various species, primarily chickens, ducks, turkeys and geese. The most important parameter for successful incubation is temperature, followed by rotation, humidity, and ventilation. The end of a successful incubation process is hatching, followed by brooding of the young birds in a chick brooder.

Temperature

The ideal incubation temperature for birds is remarkably similar for all species. A common incubator is therefore able to incubate all types of poultry without modification to the temperature settings. Some variation in temperature is acceptable, as long as the eggs to not overheat. Do not allow temperatures to exceed the recommended temperature, even for only a short period of time. Although it is not recommended, slightly lower temperatures will not kill the chick embryos. Lower temperature can, however, increase incubation times and produce weakened chicks. Temperatures only a degree or two above the recommended temperatures, though, can kill chicks within 15-30 minutes, depending on how high the temperature is and the stage of development of the chick embryo.


Incubation parameters for different types of domestic poultry
Bird Incubation Period (days) Temperature °F/°C Humidity %
Chicken 21 100°F/38°C 55-65
Duck (Mallard Type) 28 100°F/38°C 70-75
Duck (Muscovy Type) 33-35 100°F/38°C 70-75
Goose 25–28 70-75
Ostrich 35–45 97.5/36.5 30-35
Pheasant 24
Pigeon 18
Quail 16–21
Turkey 21–23 100°F/38°C 55-60

Design of incubation systems

Heating element

Keeping the incubator warm enough for chicks can be accomplished through a variety of heating methods. Early incubators employed a kerosene wicked lamp with a bi-metallic strip thermostat that adjusted the height of the flame. Today's heating elements can be a variety of types. Perhaps the simplest of which is the use of common incandescent light bulbs and their fixtures.

Redundancy

It's important to build an incubator with a high degree of reliability in order to protect the lives of the unborn animals that are being hatched. With light-bulb heating, this is accomplished through redundancy, in other words, if a bulb were to burn out, there should be enough heating power (wattage) in the bulbs that remain to maintain the proper incubator temperature. This means that at least two bulbs should be used.

Bulbs as heating element

Bulbs in series

With two bulbs connected in series the voltage (and therefore the wattage) of each bulb is cut in half. This dramatically reduces the color temperature of the bulbs increasing the proportion of the energy released as heat and decreasing the amount of visible light given off. The second effect of this decrease in wattage is a dramatic increase in the life of the bulb, causing the filament of the bulb to last over ten times as long as it would under the normal voltage.

The drawback of bulbs in series is that if one bulb burns out, both will go out since the current flows through both filaments and a burnt out bulb functions the same as a cut wire.

For incubators that will be used frequently, one recommended strategy to get the most out of lightbulbs used as heating elements is to connect bulbs in a minimum of two sets of two bulbs. Within each set of two bulbs, the two bulb are connected to the other in series rather than the typical parallel arraignment. The two sets are then connected to each other in parallel.

The two sets of two bulbs function in parallel so that, increased bulb life, lower color temperature and redundancy are achieved.

This technique is not necessary in small incubators or those that are infrequently used since the extra expense and space required for additional bulbs, wiring and fixtures is not justified by the small increase in efficiency achieved with only infrequent use. Reliability can alternately be achieved by using a new bulb at the start of each incubation cycle (use the old one for lighting!)

Thermostats for incubators

Humidity controls

Egg turning

Eggs must be turned daily in order for successful incubation. This simulates the behavior of a hen who constantly adjusts and "stirs" her eggs. At a minimum the should be turned by at least 90° 4 times per day.

Turning by hand

A useful technique is to mark the eggs with a pencil, with an "X" on one side and an "O" on the other side for example, to track the turning. All the "X's" should be turned to the "O" side; this helps the farmer to keep track of which eggs have been turned and which have not

Devices to turn eggs

  • "rack" devices
  • tray devices
  • rolling devices