Rate of Comb Growth in New Hampshire Cockerels as Related to Their Subsequent Reproductive Performance in Flock Matings

A MEANS of predetermining reproductive performance in young breeding cockerels would be considerable economic benefit to poultry breeders and to the hatchery industry. It is generally known that the comb of the male fowl is a secondary sex organ and that its size is influenced by the male sex hormone secreted by the testes. It has been observed in developing cockerels that periods of greatest comb growth coincide with periods of greatest testicular growth (Blyth, 1928; Parker, McKenzie and Kempster, 1942; Fransen, Andrews and Carrick, 1955). Hogue and Schnetzler (1937) found that, after 16 to 20 weeks of age, Barred Rock cockerels with large combs and wattles were more likely to fertilize eggs than those with small combs and wattles. Jones, 1944, has shown that in Leghorns rate of comb development is associated with spermatogenic activity. In order to determine the relation of rate of comb development in New Hampshire …