154 HOW I MADE $10,000 IN ONE YEAR 



We have also found ground for the belief that a two- 

 year-old hen is more or less immune from infection by 

 one a year younger. This cannot be given as an estab- 

 lished fact because the particular two-year-old may have 

 been one of the immunes. But in the development of 

 the disease we had the same experience in both our 

 sieges, the disease ran through different yards of hens 

 of the same age at the same time, leaving the younger 

 or older free of it ; and when it attacked the birds of the 

 other age, it ran through all of the birds hatched in that 

 year regardless of where they were kept. 



It has been noted that 30 per cent of the birds were 

 affected. Of this 30 per cent, 25 per cent either died or 

 had to be put out of the way because of canker in both 

 eyes. This indicates a mortality of 7^ per cent. The 

 figure may not be taken as entirely accurate for the reason 

 that it includes ordinary mortality which was not neces- 

 sarily due to the pox and canker. It was found imprac- 

 ticable to distinguish. 



A flock attacked by this disease will show a decrease 

 of from 50 to 60 per cent in egg production ; a flock that 

 has been laying 1,000 eggs will drop to four or five hun- 

 dred, and the production will reach the minimum in a 

 very short time. 



The disease runs its course, in a large flock, in from 

 60 to 70 days. In that time the egg production will again 

 resume normal proportions, allowing for the mortality 

 and for the time of year. It is our experience that the 

 loss in production will be made good by heavier laying 

 later in the same season or by abnormally high pro- 

 duction in the season following. The pullets attacked 



