In chickens, the frizzle gene “F” controls the appearance of the feathers. A homozygous dominant chicken for the frizzle gene shows “extreme frizzle”, that is his feathers are extremely disrupted. The normal chicken is homozygous recessive and has undisrupted feathers. When a chicken with extreme frizzle is mated with a normal chicken, all of the offspring exhibit mild frizzle.

Based on the information provided, the inheritance pattern of the frizzle gene in chickens can be inferred as follows:

• Homozygous dominant (FF) chickens exhibit extreme frizzle (extremely disrupted feathers).
• Homozygous recessive (ff) chickens have undisrupted feathers (normal phenotype).
• When a chicken with extreme frizzle (FF) is crossed with a normal chicken (ff), all the offspring (Ff) exhibit mild frizzle, which is an intermediate phenotype between extreme frizzle and undisrupted feathers.

This pattern suggests that the frizzle gene (F) exhibits incomplete dominance or codominance. In this case, the heterozygous offspring (Ff) display an intermediate or mild frizzle phenotype, which is a blending or combination of the extreme frizzle and undisrupted feathers seen in the homozygous forms.

This inheritance pattern implies that the heterozygous state (Ff) does not completely mask the expression of the dominant allele (F) but rather shows an intermediate phenotype, demonstrating incomplete dominance or codominance in the expression of the frizzle gene in chickens.