ASSESSING FERTILITY: .BREAKING OUT PARTIALLY INCUBATED EGGS:.....STEP 2

The fertility test undertaken on partially incubated eggs requires the destruction of some hatching eggs,but is easier and requires considerably less practice then examining fertility in un incubated eggs ,once again a 100 eggs sample per flock is the minimum requirement ,although it is usually more practical to use one or more full setter try.Eggs should have been incubated for 3 to 5 days proir to examination each egg should be opened very carefully from the top of the air cell so as to avoid any disruption to the egg contants,then the blastoderm or infertile disc will be on th upper surface of the yolk and very easy to see.do not spend too much time trying to identify signs of membrane development if it is not obvious it has not happened




a truly infertile egg will have the characteristic small dense white area described previously for fresh unincubated eggs

Embryo after one day in the setter.

Embryo after two days in setter

Embryos dying in the first and second day of incubation will show development of extra embryonic membrane growth over the top of the yolk.\this is characterized by a cream colored disc larger than the white doughnut in the fresh UN-incubated fertile egg.after one day of incubation the areas occupied by the extra embryonic membrane will be about one centimeter in diameter whilst after two days the membrane will occupy almost the entire upper surface of the yolk.

Embryo at the blood ring stage.

After three days of incubation,live embryos will have well developed circulatory system

Visible black eye in the devloping embryo

From day five onwards,the characteristic feature of the embryo is the black pigmented eye.the term black eye has been used to describe the embryo from day five to day 12 of incubation after which the time there is the obvious development of the feathers.