Small weak chicks with large air cells, exhausted chicks in shells that have been chipped most of the way around, and chicks glued to the shell are indications that the relative humidity was too low.Obtain fertile eggs for hatching.Large numbers of unhatched, unpipped chicks, live trapped embryos and large chicks coated with albumen are indications that the incubation humidity was too high.Late hatching of large soft chicks which are slow starting, and chicks with wrynecks, are characteristic of incubation temperatures that were too low.Early hatched, weak chicks, unhealed navels, unabsorbed yolk sacs, crooked toes, crossed beaks and a high proportion late dead in the shell, are indications that the incubation temperature was too high.Analysis of dead embryos in the shell is also a valuable problem solving tool to help refine incubation practices. This enables the relationship between the parameter, settings and hatchability to be analysed in relation to embryonic mortality. Modern electronic technology has been developed to manage variation in temperature and humidity during incubation and these parameters are monitored constantly and recorded along with the incubation settings. This is because the thermometer in still air incubators is normally located at the top of the incubator and there is a marked temperature gradient from the top of the incubator to the bottom. Incubation Period and Operating Conditions for Fertile Eggs of Domestic Birds in Forced Draught Incubatorsįor still air incubators add approximately 1☌ to the operating temperatures recommended in table 1. Most incubators rotate the eggs by approximately 90 degrees. Egg turning should be undertaken 3-6 times per day and an uneven number of rotations are better so that the eggs are not in the same position for a longer period. The turning process allows the embryo to revolve and slide in the inner white and provides access to additional nutrients for embryonic development. This phenomenon of adherence to the shell membrane commonly occurs during fertile egg storage and during early incubation (generally the first week). The hatched chick is most susceptible to oxygen deviation (compared to the pipped chick and the embryo in the intact egg), which implies that ventilation rate and carbon dioxide concentration is most critical in the late phase of incubation.Įgg rotation or turning is required to ensure that the embryo developing on the yolk does not adhere to the shell membrane. The normal atmosphere contains 21% oxygen and 0.04% carbon dioxide. Ventilation and Carbon Dioxide/Oxygen ConcentrationĮmbryonic growth is optimised at an air concentration of carbon dioxide of 0.4% and embryonic growth is depressed and mortality increased with carbon dioxide concentrations above 1%. These parameters can be easily achieved and maintained if the incubator manufacturer’s operating instructions are carefully adhered to. Turning of the fertile eggs by approximately 90 degrees several times per day by manual or automatic means.Correct oxygen and carbon dioxide concentrations controlled by ventilation.Correct humidity controlled by ventilation rate and water application.Correct and even temperature controlled by a thermometer or thermocouple.The four main essentials of incubation of good quality fertile eggs are: Principles of Artificial Incubation of Fertile Eggs Temperatures below 10☌ can inactivate the germ cell. Temperatures above 25☌ can initiate cellular replication of the germ cell on the yolk of the fertile egg and will increase embryonic mortality and reduce hatchability. Fertile eggs should maintain a relatively constant weight with minimal weight loss during storage. Optimal hatchability is achieved in fresh eggs less than 10 days old, but reasonable hatchability can be obtained in eggs up to 14 days of age. Fertile eggs should be clean and dry and stored between 12-15☌ at a relative humidity of 75% with the small end down.Įggs should be turned by 90 degrees at least once to twice daily.
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