Feather color in a certain species of bird is controlled by a pair of alleles that exhibit incomplete dominance. if birds that are homozygous for one allele are black and birds that are homozygous for the other alleles are white, then heterozygous birds would be:

The heterozygous birds phenotype would therefore be black and white because both parent genes are dominant so they would be fully expressed, none would overpower the other (no dominant or recessive) this is known as Codominance and and example of this is with the blood types.