Abreed of chicken shows codominance for feather color. one allele codes for black feathers, another codes for white feathers. the feathers of heterozygous chickens of this breed will be

The correct answer is- speckled

Explanation:

In codominance, no allele is able to mask the expression of other alleles so in codominance both the allele act as dominant allele or no allele act as a recessive allele. Therefore in codominance, both the allele is expressed in the phenotype equally.  

One of the famous examples of codominance is the ABO blood group. In ABO blood group A and B is dominant allele so when they both come together in an individual the individual blood group become AB.

So here as the chicken breed shows codominance, therefore, both black and white alleles will be dominantly expressed and the feather of heterozygous chicken would be speckled.