58 Experiment Station Bulletin 345 



sections, and a corresponding pH determination made for each section. 

 The gizzard contents were removed and preserved for later enzymatic 

 studies. 



Tabulations have been made showing (1) the composition of the 

 tour diets as used in this experimental procedure, (2) the average feed 

 consumption in pounds per chick for all groups by specified periods as 

 maintained in growing batteries, and (3) the pounds of feed required to 

 produce one pound of gain. It is interesting to note that approximately 

 the same quantities of feed were consumed by each group at the two 

 similar protein per cent levels, but the relation of feed consumed to the 

 average body weight attained at twelve weeks of age indicates that feed 

 efficiency was quite variable. 



The 19 per cent protein groups were more efficient in the utilization 

 of feed, and at both the 15 and 19 per cent levels the fish meal diet was 

 used more efficiently than the dried skimmilk diet. A difference of 0.3 

 pound for the lower protein content group in favor of the fish meal fed 

 birds was noted, whereas with the higher protein content mash this dif- 

 ference increased to 0.5 pound of feed. 



The mortality during the 12-week period was in order of groups: 

 5, 4, 6, and 3 chicks, respectively. In no case was the loss excessive. 

 Pneumonia was the chief cause of mortality. (A. E. Tepper, T. B. 

 Charles, S. R. Shimer, H. A. Davis) 



Cause and Prevention of Gizzard Lesions in Chickens 



Last year the progeny of certain families of chicks showed a lower 

 incidence of gizzard erosions than other families. On the basis of this 

 four pens of hens were made up, the first, from a family with extremely 

 low incidence; the second, a family of high incidence; the third, an inter- 

 mediate group ; and the fourth, a mixed group of high and low birds. 

 Eggs were obtained from these four pens of birds over a period of 16 

 weeks. The chicks hatched from these eggs were killed after 24 hours 

 and the gizzard lesions examined and scored. Birds belonging to the low 

 group remained low, and those in the high group remained high. How- 

 ever, the difference between the two groups was not nearly so marked 

 as it was the previous year. Progeny from these two groups are being 

 raised so this test can be repeated another year. 



With 210 pedigree hatching eggs from identical dams divided into two 

 equal lots and placed in similar incubators, some temperature studies have 

 been conducted. After 450 hours of normal heat in accordance with the 

 incubator manufacturer's recommendation, one lot of eggs was subjected 

 to a temperature 5°F. below normal for a period of 12 hours and then 

 returned to normal until hatching time. All chicks hatched were killed 

 and examined. The reasoning to be checked is whether by slowing up 

 the stage of yolk inclusion in the body cavity, a slowing of the rate of 

 blood-pressure increase might also result and thus reduce gizzard lesion 

 severity. 



Various mechanical operations affecting the yolk in eggs harboring 

 well-developed embryos were performed. With all care the resulting 



