In fowls egg takes about 21 days to hatch. The relative humidity should be around 60 per cent during the first 18 days of incubation and 70 per cent in the last 3 days for optimum hatchability. Fertile eggs are loaded into the incubator with broad end up. Hatchability decreases when eggs are placed in the incubator with narrow end up as the embryo develops with its head in the small end. Turning or eggs in the incubator improves hatchability. Eggs should be turned at least 4 times during a day when turning is done by hand.
Modem incubators are provided with devices for automatic turning of eggs at least 8 times or more during 24 hours. No turning is required after 18 days of incubation. Use of separate hatcher improves hatchability. Use of separate hatcher facilitates cleaning, disinfection and fumigation without disturbing other eggs. The eggs are candled from fifth to seventh days of incubation to remove infertile eggs and on 18th day to remove dead germs.
Although infertile eggs or eggs with dead germ do not serve any useful purpose, removal of such eggs from the incubator makes the room available for setting of more eggs. In most commercial establishments, candling is done on 17th or 18th day of incubation to save labour.
Depending upon the passage of light through the egg, the eggs are classified as infertile when transparent, dead germ when translucent and eggs with live embryos when opaque. Eggs with live embryos only are transferred to the hatcher. The deaths can be produced from too much humidity during the entire incubation period or from too little humidity during the hatching period. The desired egg weight loss during incubation caused by water evaporation is about 12 percent.
If humidity during incubation is kept too high, adequate water evaporation from the egg is prevented. The chick can drown in the water remaining in the shell at hatching. A dried coating around the chick's nostrils and beak indicates that drowning was likely. Attention to maintaining proper incubation humidity during incubation will reduce the potential for this problem at hatching time.
If the humidity is allowed to decrease after the chick pips the shell, the membranes within the shell can dry-out and stick to the chick. This prevents the chick from turning inside the shell and stops the hatching process. The chick eventually dies. If the membranes around the shell opening appear dried and shrunken, the cause is probably low humidity during hatching. This condition can occur quickly within 1 or 2 minutes when the incubator is opened to remove or assist other chicks that are hatching.
When hatching begins and proper incubator conditions are attained, the incubator should never be opened until after all chicks are hatched and ready for placement in the brooder. Backyard chicken flocks continue to grow in popularity as Mississippians embrace the ability to produce some of their own food and enjoy the quirky personalities of the birds. Tom Tabler, poultry specialist with the Mississippi State University Extension Service, said those considering starting a backyard flock need to make clear-headed plans before bringing home darling little chicks.
To comply with COVID social distancing guidelines, the opportunity will be extended virtually this year. The U. While the MSU Extension science team encourages youth to ask questions and discover answers, this is one experiment we suggest you only read about instead. Because, unfortunately, the only thing that would emerge from an egg under your pillow would be an unpleasant smell. For more information about 4-H learning opportunities and other 4-H programs , contact your local MSU Extension office.
This article was published by Michigan State University Extension. Can you hatch an egg bought from the store? Photo by Cecilia Spears, Alcona County 4-H member During their exploration of chicken embryology, youth learn that for a chicken to develop from an egg it must be fertilized. Did you find this article useful? Please tell us why Submit.
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