Why can recessive white chicken leak colour?

The recessive white chicken leaks color because of the presence of a modifier gene or locus. This modifier gene is responsible for the dilution or reduction of the pigment responsible for the white color of the chicken's feathers. The modifier gene, designated as "Inhibitor of White" or "I", affects the expression of the recessive white gene (c). When the modifier gene is present, the expression of the recessive white gene is reduced or inhibited, resulting in the leakage of color. This means that instead of a pure white color, the feathers of the chicken may exhibit a range of shades, including cream, buff, or even light brown. Therefore, the presence of the modifier gene in recessive white chickens allows for the expression of other color pigments, leading to the leakage of color and a deviation from the expected pure white phenotype.