Chicken Egg Incubation Guideline

Fail to hatch

Approximately 20 percents of incubated eggs normally do not hatch. The majority of this subjected to embryo mortality that occurs during the first and last weeks of incubation. Mortality during the last three days of incubation may be the result of an accumulation of factors that weaken chicks to the point that they cannot survive the normal rigors of the hatching process.

Other causes of mortality can be related to inappropriate management or function of the incubation process. Common causes of abnormal mortality levels during the first and second weeks of incubation include improper temperature or ventilation. Incubator overheating, for example, can quickly kill the developing embryo. Early in the incubation period, overheating can also contribute to the incidence of exposed viscera (yolk sac and internal organs protruding from body cavity) in the nearly fully developed chick. Overheating, together with rough handling of the eggs, can contribute to malformed head parts, such as a protruding brain, deformed beak or lack of eyes.

Improper temperature or ventilation can also cause death during the pipping stage as chicks peck through their shells. Other possible causes of death at this late stage of development include improper humidity control, disease and even thin egg shells.

Diagnosis of failure to hatch

Break and examine the eggs that fail to hatch for certain diagnostic signs based on the appearance and comparative development of the egg and embryo. Note that this procedure can be dirty and produce unpleasant smells, so care should be taken. Break the egg into a flat container, such as an old plate, and evaluate the contents according to the following criteria:

Clears: Absence of a blood ring or embryo development indicates that either the embryos died early in incubation or the eggs were infertile.

Blood rings: Clear eggs with a formed blood ring or small embryo indicate that death occurred in the first three days of incubation. Possible causes are incubator malfunction during days 1 to 3 or improper storage of the eggs before setting.

Dead early or midterm embryos: Many factors can cause embryos to die early or in midterm. Possible causes include excessively high or low incubation temperatures, improper turning, low viability of the egg caused by parental nutrition or inheritance, improper ventilation and suffocation, disease, poor egg shell, and contamination. Embryos subjected to overheating will appear red because of hemorrhaging of blood vessels.

Fully formed but not pipped: When chicks die fully formed without pipping, the usual causes include low average incubation temperature, weak viability of setting eggs, improper humidity, genetic defects, contamination or temperature malfunction.

Malformed chicks: Random deformities may be caused by high temperature during certain formation times. Rough handling of incubating eggs may contribute to malformations, also genetic make up.

Cull chicks: Dry chicks with egg shells sticking to their down may indicate low humidity after pipping starts. Chicks hatching earlier than usual with bloody navels or navels not healed properly might indicate too high temperature or too wide temperature fluctuating during incubation. Chicks hatching later than 24 hours after the start of hatch are commonly cull chicks because they will not grow well and will be more susceptible to stress and disease challenges. Prolonged hatches typically result from poor embryonic vigor or an unbalanced environment throughout the incubation period, not just at the time of hatch.

Weak chicks may be placed in special isolation housing for their protection. However, chicks will be more settled if they are placed with other chicks.

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