What is a mummy chicken called?

There is no specific term for a "mummy chicken" in the way that we have words like "mummy cat" or "mummy bear".

However, here are some options depending on what you're looking for:

* Broody Hen: This is the most common term for a hen that is sitting on a nest of eggs, incubating them and preparing to become a mother.

* Sitting Hen: Another way to describe a hen that is incubating eggs.

* Mother Hen: This is a more general term for a hen that is caring for her chicks.

Let me know if you had something else in mind!