If two Creeper chickens are mated, what fraction of their offspring will be normal?

To understand the inheritance pattern in Creeper chickens, one must be familiar with the underlying genetics involved. The Creeper trait is a result of a lethal allele. In this case, we can denote two alleles as 'C' for the Creeper trait and 'c' for the normal trait.

When two Creeper chickens (both 'Cc') are mated, the possible offspring genotypes can be determined using a Punnett square:

1. CC (Creeper - lethal)

2. Cc (Creeper)

3. cC (Creeper)

4. cc (normal)

From this cross, the genotypic ratio appears as follows:

• 1 CC (lethal, not viable)

• 2 Cc (Creeper)

• 1 cc (normal)

Since the CC genotype is lethal, these offspring do not survive. Therefore, the successful offspring are what's relevant. Among the surviving offspring, the ratio of Creeper to normal is 2 to 1, which translates to 1 normal chicken out of every 3 viable chickens.

Thus, for the surviving offspring, the fraction that will be normal is indeed 1/3. This illustrates that when considering lethal alleles in inheritance