Poultry Sexing by Sex-Linked Characters

Correct Answer: Autosexing

From the notes (Table 6 and sex-linked traits section): Autosexing is the method of sexing day-old chicks based on sex-linked characters such as plumage colour and feather growth rate, which differ between males and females at hatch.

Why It Works

In poultry, the female is heterogametic (ZW) and the male is homogametic (ZZ). Sex-linked traits like rapid feathering (fast feathering allele on Z chromosome) are expressed differently in males and females at hatch, allowing visual sexing.

Types of Poultry Sexing Methods

• Vent (cloacal) method: Physical examination of the cloaca — most common in commercial hatcheries
• Autosexing: Using sex-linked plumage colour or feathering rate differences ✔
• Proctoscope method: Internal examination using a small instrument

Connection

This is a practical application of criss-cross inheritance — fathers pass X-linked (Z-linked) traits to daughters, enabling phenotypic sexing at hatch.