Fertility percent was estimated from 25 sets of eggs incubated between 28 and 63 weeks of age. The 18 percent protein treatment for eight weeks followed by 15 percent protein exhibited the highest fertility, and the 16.7 percent protein treatment for 12 weeks followed by 15 percent protein exhibited the lowest fertility. The remaining groups were intermediate with the 16.1 percent protein and 16 week treatment group numerically superior to the 22 percent protein and four-week group. There were no differences in egg production, and the effects were not related to male livability. The physiological basis for this is unknown.
Evidence here needs to be confirmed in future trials.
Males fed separately to six or eight weeks of age had significantly better fertility than males mixed at two or four weeks. The eight-week mixed males tended to have higher fertility than all other groups. The poor fertilities of the two or four-week mixed males were nearly identical. It was concluded that the current practice of mixing males with females at four weeks of age can contribute to fertility problems in adult broiler breeders. Semen motility index Mississippi State University scientists C.D. McDaniel, H.M. Parker, J.B. Yateman, C.D. Shultz and C.D. Zumwait said that previous research has shown the sperm motility index to be an excellent indicator of overall sperm quality.