A Guide to Incubating and Hatching Eggs
Embryo Mortality:
Unsuccessful hatches can be caused by infertile eggs or embryo mortality. Each of these conditions can be diagnosed after candling and after hatch. Examine eggs that do not hatch to estimate whether infertility or embryo death is the basis for hatch failure. Keep records of the time of embryo death; such records can suggest changes in husbandry that can increase profitability.
Embryo death predominately occurs at two periods during incubation: within the first 3 days of incubation and within the last 3 days immediately before a hatch.
Early embryo death occurs during formation of embryonic organs. Of all the eggs determined to be fertile by candling at one-third of incubation, 88 percent to 93 percent should continue to develop.
Death immediately before a hatch occurs during the transition between living in an egg to living on the outside. The chick can have difficulty positioning for pipping, absorbing the yolk sac, or changing to breathing air. Sometimes humidity control can be implicated in some of these problems. An overall hatch of more than 85 percent to 90 percent can be achieved. Collect and examine all unhatched eggs to determine the cause of hatch failure.
An appropriately developed chick within the egg will show certain characteristics. Normally the head is under the right wing. The air cell will be large enough to allow the chick to position correctly for hatching. The shell membranes should not dry to the chick during hatch. Note any dryness. Note the condition of the beak, wings and legs for proper form. All abnormalities should be recorded and analyzed to determine if hatch failure resulted from fertility or environmental problems that can be corrected by changing management procedures.
Use the "Hatchability and Mortality Record" to calculate the percentage fertility, percentage hatchability and percentage of total eggs hatched. These numbers will help in evaluating hatch efficiency. Any change in these figures, or a change in the distribution in mortality records are early warnings to correct small problems before they become serious.
Temperature and humidity during storage
Positioning and turning eggs during storage
Temperature, humidity and ventilation of incubator
Signs of Deficiency in the Embryo