288 Genetic Studies in Poultry 



encountered cases where a bird might go broody in her pullet year, and 

 yet show no sign of broodiness the following season. 



The material was the same as that used in the egg-colour work. 

 Both the Brown Leghorn and the Hamburgh strains were under 

 observation for some years and in neither of them did we ever observe 

 any sign of broodiness. The broodiness of the Langshan we took on 

 trust when we purchased our original birds. Such hens as we bred and 

 had under observation went broody, though we never actually made use 

 of them for sitting. 



As in the ,ca8e of egg-colour we found a marked difference in the 

 Hamburgh x the Brown Leghorn crosses, ^i birds ex Brown Leg- 

 horn % X Langshan ^ went broody, and this was also true of the 

 reciprocal. , 



In the F2. birds the distribution of broody and non-broody was as 

 follows : 



Broody Non-Broody 



Ex Brown Leghorn $ x Langshan $ 19 47 



Ex Langshan $ x Brown Leghorn J 8 8 



The birds were kept only during the pullet year and had we been able 

 to keep them for another season it is possible that the proportion of 

 broody birds would have been increased. 



The data from the Hamburgh cross are of very different type. 

 Three F^%% were used, of which one, % 64/12, never went broody over 

 three seasons, while the other two ( % 453/13 and % 454/13) only showed 

 slight signs of broodiness. Two ^ ^ were used, viz. ^ 908/12 and ^ 

 452/13. Presumably both carried some factor for broodiness since 

 cf 908/12 gave broody daughters with the non-broody % 64/12 and 

 </* 452/13 gave a broody daughter with pure Hamburgh %%. As is 

 shown by the figures seft out below the proportion of broody birds arising 

 from the Langshan x Hamburgh cross is very much lower than that 

 from the Leghorn x Langshan cross. 



Broody Non-Broody 



^2 generation $64/12x^908/12 2 2 



$453/13x^908/12 1 19 



$ 454/13 X <J 452/13 1 13 



FiX Hamburgh ? 64/12 x Hamburgh (J — 8 



Hamburgh? x (J 908/12 — 6 



Hamburgh? X ^452/13 1 21 



The small proportion of broody birds produced from the Hamburgh 

 cross is also shown by the following experiment. One of the two non- 

 broody birds of the i^a generation from % 64/12 Xc^ 908/12 was % 250/13, 

 a hen which was full black in plumage, laid a deeply tinted Q,gg (PI. IX. 



