Sexual Maturity of Males Representing Twelve Strains of Six Breeds of Chickens , ,

INFERTILE eggs represent an estimated 10 to I5 percent loss of all eggs incubated, Taylor (1949). The influences of temperature, season, and age on fertility in chickens have been investigated by a number of workers. Heywang (1944) reported that high temperature is one important factor influencing the commonly observed summer decline in fertility. Wheeler and Andrews (1943) and Parker and McSpadden (1943), found that season influences spermatozoa production in males. These workers reported an increase in sperm production from December through April and a decline during the summer and fall months. Taylor (1949) suggested the possibility of using cockerels from early spring hatches as breeders to improve fertility during the summer and fall months instead of yearling or older cocks. Jull (1935) compared the fertility of males during their cockerel year and later during their yearling year. He found advantages in favor of the cockerels of 4.85 and 11.1 percent…