Question

internal fertilisation occur in hens .but hens lay eggs and do not give birth babies explain

Answer 1

A baby chick hatches out from an egg laid by a hen. Development of chicken 's embryo takes place inside the female body. This type of fertilisation is called internal fertilisation.
In this process, male and female gametes fuses inside the body of female hen to form zygote. Then zygote divides repeatedly and moves down to fallopian tube to form an embryo. This results in a white coloured hard shell on embryo. After this hen lays the fertilised embryo and hatches it to make the chick come out from the egg.
Hope it helps.

Answer 2

Hens isfrom the bird group.This is because birds are the only animals with feathers.They have beaks and wings,but not all of them can fly.