320 NATURAL INCUBATION AND BROODING 
exceptionally hot weather in the summer or late spring, it is well 
to leave an open pan or low bucket on the ground, so that, when 
the birds desire, they can immerse their plumage in the water. 
Cleanliness in the sitting coop or nest is of paramount import- 
ance, since it means the prevention of vermin, improved health 
of the hen, and more ideal conditions for the chicks. Three points 
should be here considered: (1) The droppings should be frequently 
removed, as well as any cracked shells or extremely dirty litter. 
This can best be done when the birds are off the nest to eat. (2) 
An abundance of dust should be provided in a box within easy 
access of the nest, so that the sitting hens can dust themselves, 
which is just as essential to them as a bath is to human beings, 
and it also helps to keep away body lice and mites. (3) The neces- 
sity of dusting the hen with a good insect powder once or twice 
during the incubation period. The most convenient times are on 
the seventh and fourteenth days when the eggs are tested. 
Testing the Eggs.—In order to determine the fertility of the 
eggs and the development of the embryo, which is the gauge of 
the efficiency of the hatch, it is advisable to candle eggs at least 
once, and probably twice, during the hatch. This process is 
described in the following chapter (p. 343). 
Take out all which will not hatch, thus enabling the hen to 
better cover the remaining eggs. Or, when fertility is rather low 
and two or more hens are sitting, take the fertile eggs from one 
hen and put them under others. If the eggs are tested twice dur- 
ing the hatch, the most convenient times will be on the seventh 
and fourteenth days. In natural incubation it may be best to 
test but once, since testing has a tendency to disturb the hen 
more than some consider advisable. 
Hatching Records.—It is a desirable plan to have a book or 
loose leaf sheets containing a record or register of the hatching 
operations for the season. Such records can be kept for future 
reference and will materially aid in studying the results and the 
methods which brought them about. Such a record should show 
for each hen the breed of eggs, the date set, the date on which the 
hatching is expected, the number of eggs set, the results of the 
tests on the seventh and fourteenth days, the number of eggs 
broken, the number of vigorous chicks hatched, the percentage of 
the hatch, and general remarks as to results. Such a record will 
show the keeper when his hens are due to hatch, when fertility is 
running low, and perhaps enable him to make a pedigree hatch. 
