Artificial incubation. 
39 
the age of the egg the less the animal heat contained in it, and the weaker the germ ; therefore it is necessary 
to restore the original heat of the egg itself previous to starting incubation. A trial will soon prove this. 
In fact, in Nature a hen lays a certain number of eggs before going broody ; at the date of going 
broody the first egg may be a fortnight old, but watch the hen. She lays an egg, and soon 
goes away cackling ; as the eggs increase in number so she stays longer on the nest, and 
by her own bodily heat renews that which the staler eggs have lost. When she stays a long time on 
the nest we say she is going " broody," and finally she does not leave the eggs until hatched, except for food, 
etc. The Incubator eggs should be turned twice a day half round ; if not convenient once a day will do, 
but the percentage of chicks will not be so high as if turned twice, while even three times is advisable where 
one has the time and a large number of machines, or large machines. A hen is constantly moving her eggs, 
and also constantly changing their position for ventilation purposes. The reason for turning eggs is this : 
The yolk is anchored in a double manner (when lying on its side) from above and below. The top 
connection being slack when not in use, the yolk floats with the germ on the upper ])art, and the lower 
ligatures anchoring the yolk are in tension. As soon as the egg is placed on its side, the yolk gradually 
rises until the ligature is taut, and then a scarcely perceptible upward motion continues, gradually stretching 
the ligatures till they not only lose tone and elasticity, but the yolk itself, as that part where the germ is 
situated comes in contact with the inner lining of the shell, undue evajjoration, etc. takes place, and the 
Fio. 33.— Clear or Barren Egg. Fig. 34.— Fertile Eggs at about the 
fiflh day. 
germ is destroyed. Some eggs seem to lack tone and elasticity and toughness in this ligature, with the result 
that under ordinary conditions they will not hatch, but would do so were the position continually and 
frequently changed. After incubation begins the albu men in the egg changes, and becomes much less 
dense, and of a very liquid character, and as it, therefore, exerts less pressure on the yolk, the ligatures have 
a greater strain on them. Observant Fanciers may have often noticed a small dark speck, varying from the 
size of a pin's head to a pea (according to the stage of incubation), which adheres to the side of the egg. 
This is a case as above, where the yolk has risen to the top, and the germ perished. Eggs will kecj) longer 
in cold weather than in warm, on account of the different density of the albumen (that is, fertile eggs). At 
about the third day, for white-shelled eggs, and the fifth for dark or tinted ones is a good time for testing. 
All clear eggs can be used for household purposes up to the eighth day, after that they can be used for 
chicks, but even then they excel the average shop " fresh egg " in quality. I have often had all the eggs 
hatch out during .the night, only one or two being " pipped" the previous evening ; but all the eggs in the 
machine were quite fresh when put in. Fresh eggs .always hatch first, and may be recognised by the small 
size of the air-bubble or chamber. Leave the chicks in the machine till dry, and then transfer to the drying 
box, with which some machines are provided. I use a sixiall cocoa box, lined with flannel or anything warm 
and soft, and placed in the vicinity of the Ir.cubator lamp. Leave them for, say, 24 hours, warm, but not 
