388 POULTRY BREEDING AND MANAGEMENT 



egg and in the ovaries of the hen, as well as in the chick 

 when hatched. A diseased ovary produced a dis- 

 eased ovum or egg, and a diseased egg produced 

 a diseased chick, and a diseased chick may infest 

 many other chicks in the brooder. It was also 

 proved that the infection may be carried from the adult 

 hen to another through the medium of the feed. Chicks 

 of low vitality succumb more readily to the infection than 

 those of good vigor. Again, chicks hatched in winter and 

 late fall are not so subject to the disease as those in late 

 spring and summer. 



The influence of vitality is very clearly apparent. How 

 far we can count upon vitality to ward off the disease or to 

 maintain immunity, is not clearly established by the ex- 

 periments. They emphasize the importance, however, of 

 maintaining at all hazards the vitality of the stock. They 

 also offer a possible explanation of the usually larger death- 

 rate of chicks in large flocks than in small ones. One hen 's 

 chicks may be affected, another's may not. If the chicks 

 from two hens are brooded separately, the chances are the 

 one lot will live and the other may die. If they are brooded 

 together, they all may become affected and all may die. 



In white diarrhoea the deaths usually occur when the 

 chicks are under four weeks of age. In describing the 

 symptoms of the disease, Woods says: "The weakling is 

 almost always big bellied, the abdomen protruding to the 

 rear so that it punches out behind, and out of line with 

 the vent, with the result that the chick looks as if the tail- 

 piece and backbone had been pushed forward and in just 

 above the vent." Upon dissecting the chick the following 

 conditions will be found : 



"Crop. Empty or partially filled with slimy fluid or 

 with food. 



