Egg Production Rate and Fertility in Inbred Chickens

Abstract

THERE has been an increasing amount of interest in inbreeding and hybridizing chickens which has become an important phase in many poultry breeding programs. The effect of inbreeding on the reproductive capacity of chickens influences the decision concerning the following: number and size of the inbred lines, ways of testing inbred lines, rates and ultimate levels of inbreeding and eventual commercial use of the surviving lines. As an example, if reproductive capacity is not greatly reduced, the most efficient methods will tend toward starting with many small lines, using intense inbreeding carried to high levels, practicing intense selection between lines continuously, and expanding the surviving lines rapidly in order to test in crosses. On the other hand, if reproductive capacity is greatly reduced, selection within lines would be emphasized instead of selection between lines. The lines would need to be larger and the process of making and testing lines would . . .