Explain the process of reproduction in hens.
In case of hens, soon after fertilization, the zygote divides repeatedly and travels down the oviduct. As it travels down, many protective layers are formed around it. The hard shell that you see in a hen’s egg is one such protective layer. After the hard shell is formed around the developing embryo, the hen finally lays the egg. The embryo takes about 3 weeks to develop into a chick. The hen sits on the eggs to provide sufficient warmth. The development of the chick takes place inside the egg shell during this time. After the chick is completely developed it bursts open the egg shell.