Doesn't look at all cuckoo to me--cuckoo would show up on more than just the tips of the feathers.
Very poorly laced (Pgpg Mlml) perhaps? Doesn't look like large enough spots to be mottled.
Does the colour show up on other than the breast?
Barring is dominant, so it would show up if present. The only way barring shows up partially is if another gene restricts it from certain parts of the body. But even then, entire feathers are barred.
Cuckoo hen to black or blue male will give sex linked barring: barred males and black or blue females. Cuckoo male to black or blue female will not create sex-links--all offspring will be cuckoo if the male is homozygous for barring; half of the offspring, irrespective of gender will be barred is he is heterozygous.
Very poorly laced (Pgpg Mlml) perhaps? Doesn't look like large enough spots to be mottled.
Does the colour show up on other than the breast?
Barring is dominant, so it would show up if present. The only way barring shows up partially is if another gene restricts it from certain parts of the body. But even then, entire feathers are barred.
Cuckoo hen to black or blue male will give sex linked barring: barred males and black or blue females. Cuckoo male to black or blue female will not create sex-links--all offspring will be cuckoo if the male is homozygous for barring; half of the offspring, irrespective of gender will be barred is he is heterozygous.