GENETICS 2010 Poultry Science 89:1360–1371 doi: 10.3382/ps.2009-00593

embryonic oxygen uptake ABSTRACT High ambient temperature is a major fac-tor for diminishing reproductive performance of broiler parent stocks. Homozygous naked neck (NaNa) broil-ers, which possess a higher adaptation to heat due to a reduction of feather coverage, exhibited higher growth rates and meat yield. This study was conducted to in-vestigate the influence of genotype × temperature in-teractions on the reproduction traits of heavy broiler dams caused by different feathering genotypes induced by naked neck gene (Na). In an additional experiment, the effect of Na gene on embryonic activity using ox-ygen uptake was examined. Normal-feathered (nana) and NaNa hens were maintained in separate cages un-der high (30°C) and moderate (19°C) temperatures