476 ARTIFICIAL PROPAGATION OF GROUSE 



Anyone wishing to experiment with or to raise grouse in numbers will make better progress 

 by undergoing a year's training in incubator operations or by employing and watching a 

 skilled operator. The operation is not too difficult for, although grouse egg incubation 

 requires certain techniques all its own, in general it is handled much as are other game birds' 

 egga. 



This is very important because poor incubation is one of the cardinal reasons for the loss 

 of many grouse chicks from two to five days alter hatching. The probability of chicks sur- 

 viving after hatching varies, in general, directly with the percentage of fertile eggs hatched. 



At the Research Center, the average of the fertile eggs hatched has been 72 per cent with a 

 high for one season of ST^/o per cent. This is encouraging as it compares very favorably with 

 the hatchability of the eggs of other game birds which have, through the years, been fully 

 adapted to artificial propagation. 



Location of tlie Incubator. To assure good hatches there are certain factors to be taken into 

 consideration. One of these is the proper location of the incubator. Successful operation 

 requires a room well ventilated but not subject to sudden marked changes in temperature or 

 humidity. Windows should be located so that tbe incubators will not be subjected to direct 

 drafts or sunlight. Room temperature between 60 and 70 degrees are a distinct aid to effi- 

 cient incubator operation. About the same degree of humidity is desirable. Concrete floors 

 help to make the room rat-proof and easier to keep clean. 



Type and Care. As with people, each incubator has its own peculiarities and limitations. 

 Of the two types tested at the Center, still and agitated air, the former is preferred because 

 it is simpler and easier to control and the chicks hatch better. Since large numbers of eggs 

 are seldom involved, a small "still air" sectional machine, electrically controlled, has given 

 satisfaction since 1934. A single section handles up to 180 eggs in turning trays made for 

 pheasants. At the Center two of these sections are used for hatching, and four for incubation. 



Pedigree hatching trays are necessary to permit the wing banding and identification of each 

 chick for the selective breeding program. 



An incubator is only as good as its temperature control. Failures of this important mecha- 

 nism are doubly costly. Reliable thermostats and thermometers are therefore a sound invest- 

 ment. At the beginning of each breeding season the former should be checked for leaks and 

 the latter for accuracy. 



The incubators always should be kept scrupulously clean and should be disinfected at the 

 end of each season. To give time for necessary adjustments, the machine should be leveled, 

 put in operation and carefully checked for at least 72 hours before the first grouse eggs are 

 set. 



Incubator Operation. There are several ways of determining how best to operate an incu- 

 bator. In the absence of previous experience one must be guided by the manufacturer's 

 instructions. Later, knowledge born of past results proves the best mentor. In the early days 

 of the Investigation few grouse eggs had ever been incubated artificially. Nothing was known 

 of the adaptability of any of the commercial incubators for such a purpose. Dr. A. L. 

 Romanoff, Professor of Experimental Embryology at Cornell had, however, successfully 

 hatched grouse eggs for some of Dr. Allen's experiments. Because of the widespread applica- 

 tion of this technique to the propagation of game birds, beginning in l').'^2 and continuing 

 for five years. Dr. Romanoff'^' carried out a study of game bird im ul>ali<iii requirements. This 

 was based on the three im|i(>rtant physical factors of incubation — temperature, humidity and 



