A comparative analysis of indicators of fertility duration in hens

1. This study identified the most effective indicator for assessing the duration of fertility (DF) in chickens by comparing six potential indicators; number of fertilised eggs (NFE), maximum number of fertilised eggs continuously produced (MNFE), effective duration of fertility (EDF), fertility duration day (FDD), maximum duration of fertility conditional (MDFC) and maximum duration of fertility (MDF).2. This study used 1162 Xinhua chickens in two groups: 764 parental (unselected) and 398 selected (first-generation obtained from the parent MNFE > 6) groups, with three lines (B, C and D) in each group. Data from two artificial insemination cycles (17 d) in 60-week-old birds were used to calculate the indicator value. Subsequently, a comparative analysis of the indicators, heritability, selection response and repeatability was conducted within and between groups to assess genetic and environmental influences. Correlation analysis was performed to evaluate the relationship between the indicators and egg production status (unfertilised egg production (UEP), total egg production number (TEP) and individual fertility rate (IFR)).3. Comparing the two groups, there were significant (p < 0.001) differences in all indicators except MDFC and MDF. Among the indicators, NFE exhibited the highest heritability (h²  = 0.23), the strongest selection response (R = 0.80) and the highest repeatability in both groups. Analysis showed that NFE was significantly (p < 0.001) correlated with all indicators and highly correlated with TEP(r = 0.73), IFR (r = 0.74) and negatively moderately correlated with UEP (r = -0.49).4. The data suggested that NFE was the most reliable DF indicator, offering consistency and comparatively higher genetic influence.