In a still-air incubator, where the eggs are turned by hand, it may be helpful to place an 'X' on one side of each egg and an 'O' on the other side, using a pencil. Never set eggs with the small end upward. This enables the embryo to remain oriented in a proper position for hatching. The eggs are initially set in the incubator with the large end up or horizontally with the large end slightly elevated. The air vents should be almost fully open during the latter stages of hatching. Keep the incubator closed during hatching to maintain proper temperature and humidity.

The embryos are moving into hatching position and need no turning. Do not turn eggs during the last 3 days before hatching. Unobstructed ventilation holes, both above and below the eggs, are essential for proper air exchange.Įggs must be turned at least 4-6 times daily during the incubation period.

Care must be taken to maintain humidity during the hatching period. As embryos grow, the air vent openings are gradually opened to satisfy increased embryonic oxygen demand. As the chicks hatch, they require an increased supply of fresh oxygen. While the embryo is developing, oxygen enters the egg through the shell and carbon dioxide escapes in the same manner. Ventilation is very important during the incubation process. Humidity is maintained by increasing the exposed water surface area. Increased ventilation during the last few days of incubation and hatching may necessitate the addition of another pan of water or a wet sponge. The water pan area should be equivalent to one-half the floor surface area or more. Rarely is the humidity too high in properly ventilated still-air incubators. Conversion between the two humidity measurements can be made using a psychrometric table. The two terms are interconvertible and actual humidity depends upon the temperature (F.) as measured with a dry-bulb thermometer. Most persons in the incubator industry refer to the level of humidity in terms of degrees F., (wet-bulb) rather than percent relative humidity. When hatching, the humidity is increased to 65 percent relative humidity or more.įrequently there is confusion as to how the measurement of humidity is expressed. The relative humidity in the incubator between setting and 3 days prior to hatching should remain at 58-60 percent or 84-86º F., wet-bulb. Humidity is carefully controlled to prevent unnecessary loss of egg moisture. Do not allow the thermometer's bulb to touch the eggs or incubator. The temperature is measured at the level where the embryos develop (at the top of the egg). If the eggs are positioned in a vertical position, elevate the thermometer bulb to a point just below the top of the egg. Obtain the proper temperature reading by elevating the bulb of the thermometer to the same height as the top of the eggs when the eggs are laying horizontal. to compensate for the temperature layering within the incubator. Maintain a still-air incubator at 102 degrees F. In both cases the total chicks hatched will be reduced. One that runs consistently cooler tends to produce late hatches. A forced-air incubator that is too warm tends to produce early hatches. High temperatures are especially serious. Prolonged periods of high or low temperatures will alter hatching success.

Minor fluctuations (less than ½ degree) above or below 100 degrees are tolerated, but do not let the temperatures vary more than a total of 1 degree. throughout the entire incubation period when using a forced-air incubator. Obtain the best hatch by keeping the temperature at 100º F. Poor results also occur from improper ventilation, egg turning and sanitation of the machines or eggs. Improper control means that the temperature or humidity is too high or too low for a sufficient length of time that it interferes with the normal growth and development of the embryo. Poor results are most commonly produced with improper control of temperature and/or humidity. The chart shown below lists the major incubation factors and the values of each that produces the best incubation conditions for the species of birds shown. When incubating any bird egg it is important to control the same factors of temperature, humidity, ventilation, and egg turning.

Humidity of incubator for chicken eggs