218 POULTRY BREEDING 
places not be available it is entirely possible to operate 
an incubator in any room, and thousands of chicks are 
hatched in vacant bed-rooms, kitchens and even living- 
rooms. The modern incubator is finished so that it does 
not detract from the appearance of a room, even a well- 
furnished one. 
We have dispensed with all devices for turning the 
eggs; the best incubators do not have them. The best 
way to turn eggs in an incubator is by hand, one at a 
time, or by taking a row of eggs from one side of the 
tray and with the flat hand gently rolling those remain- 
ing in the tray over to the side the eggs were taken from, 
replacing the eggs which were removed in the space left 
empty on the side opposite from where they were taken. 
It is not necessary to turn eggs half over. The hen 
merely stirs the eggs under her by running her beak 
among them, by moving them with her feet and by 
changing their position by a shaking motion of her body. 
We believe in cooling eggs. We have had better hatches 
by following this method. The embryo chick receives 
its supply of oxygen through the pores of the shell, as 
its lungs have not developed to the stage of use. If the 
eggs are cooled down about 15° every day the air inside 
the shell contracts and to supply the vacuum thus left 
outside air is drawn into the shell, thus insuring a larger 
supply of oxygen than would have been possible had 
not the eggs been cooled. 
We turn eggs every morning and evening Take the 
egg tray out of the egg chamber and set it on the top of 
the machine or on a table kept conveniently close to the 
machine. Shut the door of the machine and then turn 
the eggs with care, taking about 10 minutes to do it. If 
the weather is very warm leave the eggs out from 20 to 
