'f^-^''h *i 



' ^'' ^ 



Figure 13. Dead Embryos. Pullorum disease affects hatchability. At the end of the incuba- 

 tion period, embryos may either be dead in the shell or be too weal< to emerge from the shell. 

 Embryos IV and V were removed from the shell on the twenty-first day of incubation. S. pullorum 

 was isolated from embryos III, IV, and V. Pullorum disease should not, however, be regarded 

 as the only cause responsible for low hatchability. Refer to question 29. ,k_. _« _ 



Figure 14. Collecting Blood Samples in the Field. 

 The birds are confined in a wire enclosiu-e in the pen. After each bird is leg banded, a small 

 sample of blood is collected from the wing vein into a small vial labeled with the leg band number. 

 Refer to question 38. 



(16) 



