TYPES OF INCUBATORS 333 
The type selected will depend largely upon the number of eggs 
to be hatched, the mammoth incubator being best adapted to large 
poultry plants, or community centres where there is a demand for 
custom-hatched and day-old chicks. It is being used to some 
extent on large broiler plants, and more and more in commercial 
hatching; but its popularity is only of recent origin. In custom 
hatching a compartment or a number of compartments are rented 
at so much per hatch, the person who hires the compartment 
supplying the eggs and taking the chicks, and the operator fur- 
nishing the heat and doing the work connected with running the 
A Thermostat E 
B Lever weight, to balance 
C Connecting rod and thumé nut 
D Lever arm 
= Lamp damper which controls the 
heat entering and leaving 
the heater flue. 
Fic. 159.—A complete self-regulating device for incubators heated by lamps. 
machine. The chief advantages of this are its large capacity and 
small cost for labor and fuel. 
Profitable hatching by artificial incubation depends upon 
securing a good incubator in a good location. Some of the points 
to consider in selecting an incubator are: 
The machine should be best adapted in size to the conditions, 
—the mammoth incubator where thousands of chicks are to be 
hatched within a short time, the individual lamp machine for 
much smaller numbers on small poultry plants or farms. 
The simplicity of the machine should always be taken into 
account. The more mechanism there is, the greater the danger 
of mistakes in management; the more parts there are to get 
out of order and work poorly, the less satisfactory the machine 
will be. 
Since the effectiveness of the machine depends in great measure 
upon the maintenance of a uniform temperature of desired degree, 
the regulating apparatus should be carefully examined (Fig. 159). 
This apparatus should combine four requisites: (a) A sensitive 
well-built thermostat; (6) a simple but certain method of trans- 
