What is a rooster chicken?

Here's a breakdown:

* Chicken: This is the general term for a bird of the species *Gallus gallus domesticus*.

* Rooster: This is the specific term for an adult male chicken.

* Hen: This is the specific term for an adult female chicken.

So, "rooster chicken" is redundant, but it's often used colloquially to emphasize that the chicken is male.