Errors in Paternity Resulting from the Double Shift of Males

A MAJOR handicap faced by poultry breeders is a shortage of male birds whose genetic prepotency has been proven by the performance of their progeny. To overcome this hindrance some breeders are using a double or triple shift of males in their single-male mating pens. When using a method of shifting males, the accuracy of paternity of the chicks must be maintained at a high level to avoid errors in selection. Crew (1926) reported that if one male was replaced by another the influence of the first would disappear in seven to ten days. Warren and Kilpatrick (1929) found that if a male in a mating was replaced by another, the offspring of the replacing male very soon supplanted those of the former. They found practically no overlapping of the offspring of the two males. When replacing a male, Warren and Gish (1943) recommended artificial insemination of all females in . . .