Understanding Internal Fertilisation in Hens
Hens, like other birds, undergo a fascinating process of internal fertilisation which is crucial for the development of their eggs. Here’s how it happens:
1. Mating Process
- The male chicken, called a rooster, mounts the female hen.
- During mating, the rooster transfers sperm to the hen through a cloacal kiss, where their cloacas (the reproductive and excretory openings) meet.
2. Sperm Storage
- After mating, the hen has the ability to store the rooster's sperm in special sperm storage glands located in her oviduct.
- This storage allows her to fertilise multiple eggs over a period of time, even after a single mating session.
3. Egg Development
- As the hen’s ovaries release an ovum (egg), it travels down the oviduct.
- If sperm is present in the oviduct, fertilisation occurs as the ovum meets the sperm.
4. Egg Formation
- After fertilisation, the egg continues its journey through the oviduct, where it is coated with layers of albumen (egg white), membranes, and a shell.
- This process takes about 24 hours to complete.
5. Laying the Egg
- Once fully formed, the hen lays the fertilised egg.
- If conditions are right, the egg can develop into a chick when incubated.
Conclusion
Internal fertilisation in hens is a well-coordinated process involving mating, sperm storage, egg development, and laying. Understanding this process helps in appreciating the reproductive biology of birds and their lifecycle.