246 PROFITABLE POULTRY PRODUCTION 



oughly minced, mixed and wetted. The ducks are 

 allowed to eat as much as they wish. It is neces' 

 sary to feed some special formula like this only 

 where it is impossible to give the ducks free range 

 and an opportunity to balance up the food them- 

 selves. 



HATCHING IN INCUBATORS 



Where duck eggs are hatched in incubators care 

 ' must be given as to ventilation ; since duck eggs 

 ! are considerably larger than hen eggs they are 

 more difficult to handle. The air space in the in- 

 cubator is smaller proportionately for duck eggs 

 than for hen eggs ; hence, if one is going into the 

 hatching of duck eggs, he should give preference to 

 a machine with a larger air space than when hatch- 

 ing hen eggs. When such a machine is not used 

 the ordinary incubator will do, provided it is run 

 with greater care as to ventilation. Never should 

 duck and chicken eggs, duck and turkey eggs, or 

 duck and goose eggs be placed in the machine at 

 the same time. Only one kind of egg should be 

 used at a time. Duck eggs should be cooled longer 

 than hen eggs. Some duck raisers believe in 

 sprinkling the eggs with tepid water, especially 

 during the last two weeks. Others think it advis- 

 able to dip the eggs in tepid water daily; still 

 others do not practice either method. Much de- 

 pends upon the way the machine is managed and 

 the amount of moisture in the air of the egg 

 chamber. 



As a rule, ducklings break their shells 30 to 48 

 , hours before emerging. If unable to get out with- 

 ;^out aid^after the twenty-eighth day, they should 



