18 MASS. EXPERIMENT STATION BULLETIN 344 



Part II. External Egg Characters 



These studies include records made on eight generations in the three lines. 

 As indicated in the previous section, lines A, B, and C were developed primarily 

 on the basis of egg weight. Any classification of individual hens on the basis 

 of external egg characters must be purely relative and must be based on 

 apparent divergences from an assumed normal condition. Complete egg 

 descriptions were taken on all mothers and daughters but no information is 

 available on the possible inheritance of the sires used. Since full brothers were 

 used as sires in all three lines, their genetic make-up should be somewhat 

 similar. 



A. Shell Texture 



Eggs were classified in shell texture as rough, ridged, sandy, or normal. Eggs 

 with irregular ridges on the surface may or may not show a sandy or harsh 

 texture. Rough eggs exhibit mineral spots. Normal eggs have a smooth 

 texture and are free from any conspicuous ridges or irregularities. For pur- 

 poses of study, the daughters from the different types of mothers were classified 

 with respect to the shell texture of their eggs. 



In line A there were 5 mothers that characteristically laid ridged eggs with 

 smooth shell texture. These dams produced 44 daughters, of which 5 laid 

 ridged eggs, 18 sandy eggs, and 24 smooth eggs. In this last group, 3 birds 

 laid ridged eggs with smooth shell texture, thus leaving 21 individuals, or 

 47.7 percent, that may be classified as normal for shell texture. There were 



8 mothers whose eggs were classed as sandy. The 72 daughters were grouped 

 as follows: 2 rough, 11 ridged, 22 sandy, and 38 smooth. Only one laid ridged 

 eggs with smooth texture, leaving 37, or 51.3 percent, normal daughters. 

 The 57 daughters of the 7 dams producing normal eggs were rated: 4 ridged, 



9 sandy, and 48 smooth. Four daughters laid ridged eggs with smooth shell 

 texture, leaving 44, or 77.2 percent, laying normal eggs. 



In line B, 3 dams described as ridged-smooth in shell texture gave 18 daughters 

 grouped as 1 ridged, 5 sandy, and 13 smooth. The one daughter classed as 

 ridged had also smooth shell texture, leaving 12, or 66.7 percent, normal 

 daughters. One dam laying ridged and sandy eggs gave 6 daughters, classed 

 as 2 ridged, 2 sandy, and 3 smooth, of which only 2 were normal. The 9 dams 

 laying sandy eggs had 59 daughters rated as 10 ridged, 20 sandy, and 32 

 smooth. Three daughters laid ridged eggs with smooth shell texture, leaving 

 29, or 49.2 percent, normal. The 13 dams rated as normal gave 90 daughters 

 classed as 1 ridged, 7 sandy, and 82 smooth. There was no overlapping in 

 classification, and the 82 normal daughters make up 91.1 percent of the total. 



In line C, one dam classed as ridged-smooth in egg shell texture gave 12 

 daughters, 2 of which laid sandy eggs and 10 normal eggs. The 7 dams classed 

 as ridged and sandy had 34 daughters grouped as 10 ridged, 7 sandy, and 27 

 smooth. There were 10 daughters producing ridged-smooth shells, leaving 17 or 

 50 percent that laid normal eggs. Two dams classed as sandy gave 34 daughters, 

 grouped as 6 ridged, 9 sandy, and 21 smooth. Two of the smooth daughters 

 laid ridged-smooth eggs leaving 19 or 55.9 percent normal. There were 14 

 dams that laid normal eggs giving 109 daughters, ranked 1 rough, 12 ridged, 

 22 sandy, and 83 smooth. Nine daughters produced ridged-smooth eggs leaving 

 74 or 67.9 normal daughters. 



