ABNORMALITIES IN EGGS
a. Foreign Bodies. Foreign bodies, such as pieces of straw, kernels of corn, or
intestinal parasites, are occasionally found in eggs. The foreign material enters the
cloaca and works up the reproductive tract (reverse peristalsis) until it encounters a
descending yolk. Since it cannot bypass the yolk, it is forced downward and becomes
enmeshed in the shell or its contents. Roundworm, usually found in the intestinal tract,
can migrate from the cloaca into the oviduct where it may become included in an egg.
Once foreign material is surrounded by the albumen of a forming egg, it becomes part
of the egg and is covered by the shell membrane and shell.
b. Malfunction of the Reproductive Tract.
(1) Multiple yolks. Sometimes multiple yolks, or an egg within an egg,
develop. Basically, all anomalies of this type result from the same kind of process, a
reverse movement of a yolk after it has progressed part way down the reproductive
tract. For example, the yolk may move to the isthmus and then (for some reason) be
forced back into the infundibulum where it encounters another yolk; the two then
progress through the tract.
(2) Blood spots. Blood spots are caused by intrafollicular bleeding at the
time of ovulation. The blood may adhere to the yolk membrane or be included in the
Section II. PREPARING A CANDLING ROOM AND ASSEMBLING EGG
When shell eggs are examined during destination or surveillance inspection, a
basic item of equipment is an egg candler, which is used for the candling process.
Candling is a visual examination of an egg, in the shell, by use of an intense light. It
permits viewing of the shell egg contents to determine individual egg quality. The
candling process must be conducted in a dark area, either a candling booth or a
candling room, with the candling light from the egg candler providing the only source of
light. This permits the inspector to view eggs in the case, as well as to fully illuminate
the shell egg to examine the egg interior for quality. A diagram of an egg candler is
shown in figure 1-4.