As stated above, the colour of the young will depend on what the recessive yellow of the cock is masking; blue or ash-red or both. One thing is certain, all the daughters will be dilute and all the sons will be intense-coloured, but carry dilute. There are a number of variables that will dictate the colour of the young; Masked by the recessive yellow, the cock could be blue bar/blue chequer, red bar/red chequer, he could also be spread. If the black hen is homozygous spread i.e. S(black)//S(black), all the young will be spread, she could also carry recessive red. If she is not homozygous spread, some of the colours listed below could be produced. The possibilities are: Black, dun, blue bar, blue chequer, dilute blue bar, dilute blue chequer, spread ash-red, dilute spread ash-red, red bar, yellow bar, red chequer, yellow chequer, recessive red, recessive yellow. If, for example, the cock is pure for ash-red dilute (under the recessive red dilute) and the hen is pure for spread and not carrying recessive red, the young will be spread ash-red cocks and dilute spread ash-red hens. If the cock is blue (under the recessive red) and the hen is pure for spread and not carrying recessive red, the youngsters will be black cocks and dun hens. Those two examples are the simplest to explain, so I hope they are of some help.