Question

How can you obtain fertilized and unfertilized chicken eggs?

Answer 1

Hint: Fertilization is the fusion of haploid gametes from male and female to give rise to new offspring, which eventually grows into an adult. The fertilization process and development of new offspring is called sexual reproduction.

Complete answer:
Fertilization is of two types:
- Internal fertilization: Internal fertilization is the fusion of male and female gametes inside the female body. Example: Chicken.
- External fertilization: It is the fusion of male and female gametes outside the female body. Example: Amphibians and fishes.

Oviparous animals are the ones that lay eggs with little or without embryonic development within the mother. Chickens produce eggs with thick calcium shells around them, which is why fertilization is internal as the sperm can fertilize the egg without having to pass through the thick shell of the egg. However, chicken can lay eggs either fertilized or unfertilized. This is because the ova released in chicken is not regulated by mating but through the pituitary gland in the brain. Their skull is thin which allows sunlight to penetrate through it. This light is enough to stimulate the pituitary glands, resulting in the release of ova.

The types of egg produced are:
> Fertilized egg – This egg is formed by the fusion of male and female gametes through mating of chicken and rooster under the right conditions. Fertilized egg is diploid. Fertilized egg actively divides by mitosis and develops into a diploid embryo.

> Unfertilized egg – This egg is produced in the absence of mating between chicken and rooster making it haploid. The cells are arrested at metaphase 2 of mitosis.
Thus, both fertilized and unfertilized eggs are obtained from the chicken naturally. A fertilized egg takes about 21 days of incubation to hatch. However, when a fertilized egg is stored at a low temperature, the development of the embryo stops.

Note: Fertilized eggs have the same taste and nutritional value as unfertilized ones. Cloacal kiss is a process in which male and female bring their cloacae together to transfer the male gamete into the female body. Fertilized and unfertilized eggs can be differentiated by using light. The fertilized eggs will appear opaque when light is passed through it.