Genetics: Analysis and Principles 5th Edition by Robert Brooker

Exercise 38

The trait of hen- versus cock-feathering is a sex-limited trait controlled by a single gene. Females always exhibit hen-feathering as do HH and Hh males. Only hh males show cock-feathering. Starting with two heterozygous fowl that are hen-feathered, explain how you would obtain a true-breeding line that always produced cock-feathered males.