Fig. 3. Showing the way in which birds of high and low vitality fill a paral- 

 lelogram and the two triangles. This clearly brings out the points of weakness 

 in development of keel, breast and abdomen in the low vitality bird. 



Fig. 4. Baby chicks just removod from the incubator. Note the difference in 

 size, shape, and attitude of the body between A and B. 



