A purebred chicken with white feathers is crossed a black feathers.All the offspring have both and feathersWhy did this happen?

Incomplete dominance is a type of inheritance in which the phenotype of the offspring is intermediate between the phenotypes of the two parents. In the case of the chicken feathers, the white and black feathers are codominant, meaning that both colors are expressed in the offspring. This results in the offspring having both white and black feathers.

Incomplete dominance is different from complete dominance, in which the phenotype of the offspring is the same as one of the parents, and from codominance, in which the phenotype of the offspring is a mixture of the phenotypes of the two parents.