Inheritance of Broodiness in Rhode Island Reds

The conclusions which are presented in this paper are based on the trap nest records of the non-standard Rhode Island Reds that have been trap-nested at the Massachusetts Agricultural Station since 1913. With the exception of a comparatively few matings made for non-broodiness or intense broodiness, matings have been made at random in respect to broodiness.

Two catagories of birds can be recognized, viz., broody and non-broody. Of course, there are various degrees of broodiness when present, but for several reasons, I shall not attempt to consider the degrees of broodiness, but will confine the discussion to the two catagories specified.

Broodiness is the normal condition of the wild bird. Without it, the race could not survive, constituted as it is in other respects. Judging by analogy with other characters there must be a definite genetic complex for its occurrence. If we disregard the heterozygous condition, all birds that show …