EGGS OF HEN

• It is a meiolecithal egg which is oval. The animal pole is found in the form of a small germinal disc.
• The vegital pole has two types of yolk viz. White yolk & Yellow yolk.
• The white & yellow yolk are found in alternate concentric rings. The outermost ring is of white yolk.
• The central part of the vegital pole is flask shaped & contain white yolk. It is called as Latebra. The narrow part of the latebra is called as neck of latebra.

• The white yolky region just below the germinal disc is called as nucleus fo pondar.
• The yellow yolk is more viscous than the white yolk.
• The innermost egg membrane is vitelline membrane which is followed by a chalazeal layer. The chalaza membrane form chalaza on both the sides. The chalaza is a spiral cord which always keeps the germinal disc upside.
• The chalazeal layer is followed by three layers of albumin which are called as inner, middle & outer layer of albumin. The middle albumin layer is comparatively thicker.
• There are two shell membranes outside the albumin layers which are called as outer & inner shall membranes. Both the shell membranes remain fused except in the broad region where they enclose an air space. The O₂ present in the air space is used by the embryo during emergency.
• The outer most egg membrane covering is called as shell which is madeup of CaCO₃ & it is porous. It is permeable to gases but impermeable to water.
• The oviduct of hen consists of three parts viz. magnum, isthmus & uterus.
• The magnum secretes chalazeal layer & albumin layers.
• The isthmus secrets the shell membranes.  The shell glands of the uterus secrete the shell.