Male chickens carry two Z sex chromosomes, while female chickens carry one Z sex chromosome and one W sex chromosome. Located on the Z chromosome is a gene for barring. Barred feathers have black and white stripes. The barred trait is dominant to the unbarred trait.

Chickens have a fleshy growth on top of the head called a comb. An autosomal trait called rose comb is dominant to a trait called single comb.

An unbarred male heterozygous for the rose-comb trait is crossed with a barred female with a single comb. What proportion of the resulting progeny are expected to be barred males with single combs? Give your answer as a fraction or as a decimal to the nearest hundredth.