240 



MASS. EXPERIMENT STATION BULLETIN 267 



late summer of 1928 there were 1202 birds on this plant, 905 of which were 

 Rhode Island Red pullets and cockerels. The remainder consisted of older 

 stock. The young birds were vaccinated cutaneously soon after they were 

 transferred from the range to the laying houses. As in flock 1, blood 

 samples were collected for the detection of pullorum disease just prior to 

 vaccinating the birds. The older birds, likewise, were not treated. No un- 

 vaccinated young birds were left as controls because of reasons similar to 

 those mentioned In connection with flock 1. The vaccinated birds were 

 divided into groups as follows: 



House 1 — 263 pullets, housed September 10, vaccinated September 12. 

 House 2 — 24'9 pullets, housed September 17, vaccinated September 20. 

 House 3 — 244 pullets, housed September 24, vaccinated September 26. 

 South long house^l49 cockerels, housed on various dates, vaccinated 

 September 27. 



Unimportant lesions, similar to those seen in flock 1, appeared shortly 

 after the vaccination and disappeared rapidly. All birds were free of fowl 

 pox and diphtheria throughout the year. Likewise, colds and roup were en- 

 tirely absent. There was no mortality whatever that could be traced to the 

 results of the vaccination. 



All birds were trapnested, and a careful study was made of their egg 

 records prior and subsequent to the vaccination in order to determine what 

 effect, if any, the vaccination might have on their early egg production. 

 The results of this study are shown in Chart 1. As stated, there were no 

 available control birds in this flock. For this purpose the early production 

 records of house 1 for 1926 were taken and are marked "Control" in the 



CHART 1. The Effect of Cutaneous Vaccination on Early Egg Production. 



