Paternity Following the Replacement of Breeding Cockerels

THE use of multiple shifts for testing large numbers of cockerels has proven of value as a method for recognizing superior sires (Hutt and Cole, 1955). Males proven to be superior by performance of approximately 50 daughters are then used in subsequent years throughout an entire breeding season of 8 to 9 weeks and produce families two to four times as large. The chief objection to the shifting or replacing of males in the breeding pens is that for a period of time the paternity of the chicks hatched may be in doubt. In practice, this uncertainty need not be a deterrent to the use of multiple shifts. The actual error in assignment of paternity is so low that it would not influence the evaluation of either parent. PREVIOUS REPORTS Crew (1926) exchanged males in two breeding pens and measured the speed with which the semen of the replacing male …