Hens and frogs are both oviparous, but their mechanisms of fertilization are different. Hen exhibits internal fertilization, whereas a frog exhibits external fertilization.

The eggs that hens lay are fertilized eggs. This means that the fusion of male and female gametes has already taken place inside the body of an organism. The development is in the embryo stage in the egg, and further development from embryo to chick takes place outside.

The eggs that frogs lay are unfertilized eggs. These eggs get fertilized when a sperm floating in water, comes in contact with them and their nuclei fuse. Thus, the fertilized takes place outside the body of an organism. Hence, it is external fertilization.

This is how the hens and frogs differ in fertilized methods.