A SMALL EGG APPEARS UNEXPECTEDLY 
Eggs laid by one hen on six consecutive days are shown in this photograph. 
one exception, of average size. 
They are, with 
The abnormally small egg appears in this series without 
the slightest warning. The hen has not had any resting period before laying it, nor does 
she take a resting period afterward. The study of many cases of this sort shows that 
small eggs are not “‘pullets’ eggs,’’ or the last eggs laid by hens, as is often supposed, but 
that they usually appear at a time of greatest egg yield, and are probably due to some 
mechanical interruption in the hen’s egg-forming organs. 
egg yield, the last two cases excepted, 
of course. 
Having investigated the records of the 
hens after they laid small eggs, it seemed 
well to inquire what they were doing 
before. Seven records seem to indicate 
that some small eggs were laid after a 
hen had had a resting period of from 
14 to 25 days. Most of the records 
show, however, that the small eggs are 
laid without any previous resting period 
cf the hen. 
The figures also showed that as a 
rule hens do not lay extremely small 
eggs at the beginning of their laying 
periods, but that such eggs are laid at 
a time when the hen is laying most 
heavily. 
It seems clear, therefore, that the 
small egg is not due to the fact that 
it is a hen’s first attempt, or to the fact 
that it is the end of her laying period, 
and represents exhausted power. A 
fairer assumption as to the cause of 
these small eggs would be that they 
are due to some mechanical interfer- 
ence with the hen’s normal functions— 
that they are laid whenever a particle 
of blood, foreign element, or an un- 
developed yolk is drawn into the 
passage where the shells are formed, 
and that contractions of the oviduct 
(Fig. 12.) 
then cause an egg to be laid completely 
formed, but without having undergone 
normal development. 
STUDY OF LARGE EGGS 
After consideration of the small eggs, 
the records of production of large eggs 
were then examined. Eighty-nine were 
found to have a total weight of 18.35 
pounds or an average weight of .206 
of a pound. 
Of these eighty-nine large eggs, nearly 
99 per cent were laid at the time of 
heavy production, and in most cases 
the hen did not rest after laying such 
an egg, but continued her uninterrupted 
yield of normal eggs. 
“The cause of hens laying double- 
yolked eggs is due no doubt to the 
simultaneous or almost simultaneous 
liberation of two yolks and_ their 
incorporation in a single set of egg 
membranes,’* or ‘‘by the successive 
discharge of separate follicles at times 
varying from simultaneous to the normal 
period and by the subsequent union of 
the eggs in the duct due to a difference 
in the rate of passage of the successive 
eggs.” 
It further appeared that in most cases 
the hen did not rest before laying a 
large egg any more than she did after 
4 Lillie’s ‘‘ Development of the Chick,” page 26. 
5 Journal of Agricultural Research, Vol. 3, No. 5, February, 1915. 
129 
