Inbreeding the Rhode Island Red Fowl with Special Reference to Winter Egg Production (Preliminary Report)

Abstract

Inbreeding reduces variability in winter egg production only when the foundation stock is largely homozygous for factors for heavy egg yield. Sexual maturity seems to be retarded in many inbred pullets so that they are very slow in beginning to lay. Body weight does not appear to be affected by inbreeding. Winter egg yield shows a tendency to decline after the degree of inbreeding passes 25 per cent., but not necessarily so. A cumulative effect may be observed in succeeding generations. Winter egg production probably depends on seven pairs of Mendelian factors. The development of a flock breeding true for these factors is entirely possible by proper methods.